


Make Thick My Blood

by themegalosaurus



Category: Supernatural
Genre: Angst, Demon Blood, Hurt Sam Winchester, Hurt/Comfort, M/M, Mark of Cain, Past Rape/Non-con, Possession, Season/Series 10, Seizures, Vomiting
Language: English
Status: Completed
Published: 2016-03-02
Updated: 2016-03-03
Packaged: 2018-05-24 10:42:28
Rating: Mature
Warnings: Graphic Depictions Of Violence
Chapters: 5
Words: 20,676
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6151003
Author URL: https://archiveofourown.org/users/themegalosaurus/pseuds/themegalosaurus
Summary: <blockquote class="userstuff">
              <p>
  <i>“You’re going to kill me, Dean,” Sam says, eventually.</i>
  <br/>
  <i>And all Dean can say is, “I think I am.”</i>
</p><p>A season 10 AU, set after 10x14 ('The Executioner's Song'). Cas finds a solution that might cure the Mark of Cain; but if they're going to go through with it, Sam has a terrible price to pay.</p>
            </blockquote>





	1. Chapter 1

**Author's Note:**

  * For [chomaisky](https://archiveofourown.org/users/chomaisky/gifts).



> This was written for the Sam Winchester Big Bang 2016 and so it has accompanying artwork by the lovely Gale (find it [here](http://archiveofourown.org/works/6123696)!). Thanks so much for being great to work with, and for producing so many great images that let me see my fic brought to life!
> 
> Thanks also to Sarah and Becky for reading this at early stages of its construction, and to L for a thorough (and thoroughly helpful) beta when it was almost done.
> 
> Finally: this fic has been in the works for a year, pretty much. It started its life as a prompt over at OhSam back in Feb 2015. The [prompt](http://ohsam.livejournal.com/800085.html?thread=4166997#t4166997) (which is spoilery, so click through at your peril!) came from chomaisky and so this fic is presented, with apologies for lateness, to them.

Dean is going to kill his brother.

The bunker; late at night. Dean is pacing down the corridor, bouncing a little on the balls of his feet. His blood is singing. He rolls his shoulders, feels the muscles shift under his skin; and looks down at the weapon he’s carrying, its worn wooden handle clasped tight in his hand. It’s a hammer: a big one, heavy. He shifts it so the clawed end is outward, and keeps on walking. He starts to whistle under his breath.

Somewhere in the warren of corridors, Sam is scared. He’s running. But he won’t get far.

Dean pictures it, sees the hummingbird pulse at Sam's throat. “Sammy…” he calls, sing-song.

Up ahead, something – a hand, a shirttail, a heel – whisks out of sight around the corner of the wall.

Dean smiles.

He doubles back, silent now, feet soft and springy beneath him, and crosses through the shooting range to cut off Sam’s path.

As he turns into the space where Sam is hiding, Dean pauses to take in the view. Sam’s backed up close against the wall, looking in entirely the wrong direction. His chest is heaving, his shirt is sweaty, and there’s a tremor running right through his body. He’s an open target.

Dean’s veins flood hot with satisfaction. It’s the same buzz he gets when he sees a woman in a bar, watches her pupils dilate and her mouth drop open, and thinks,  _ I can have you. And I don’t even have to try. _ He can take Sam, just like this; can destroy his brother completely.

It’s only three steps, half-dancing, over to where Sam stands. Dean raises the hammer.

Sam swings round, a moment too late. His eyes pan huge and his skin drains white and he lifts his arm, just a little way, before Dean brings the claw end of the hammer down hard in his skull. It sinks with a satisfying crunch, splitting bone. Blood spurts bright out of the fracture, soaking into Sam’s hair.

Sam’s eyes roll back in his head. His chest issues a weird, groaning gasp of a sound. Something gurgles in his throat.

Dean brings the hammer back up, brings it down, does it again. He doesn’t stop until Sam is sprawled on the floor, limbs squashed out like a spider in all directions and his head an unrecognisable oozing mess.

Dean grinds the heel of his boot into the space where his brother’s face used to be. He spits a wet plug of liquid down onto Sam’s chest, triumph coursing sweet through every pathway of his body. It’s better than anything: better than sex, better than driving Baby at a hundred miles an hour down an open road. The feeling of it sends Dean dizzy, giddy with glee. Looking down at his brother’s broken corpse, he begins to laugh.

~~~

It’s his own laughter that wakes him, jerking him to consciousness panting and terrified, his dick trapped hot and hard against his thigh and his limbs tangled up in his sheets. He’s in his room, in the bunker; in the dark, although that means nothing down in these windowless bowels of the building.

He lies there for a moment suspended in the shreds of his dream, catching his breath, waiting for the tightness at his crotch to subside. He refuses to touch himself. Every time he closes his eyes, a hundred different images of Sam’s smashed-up body appear behind his eyelids. Dean might be pretty far gone, but there’s absolutely no way,  _ no way _ he’s jacking off to that.

Instead, he finds his left hand creeping over his belly, settling over the Mark just below his right elbow. Tiny pinpricks of heat run over its surface, tingling at the tips of his fingers. He grips tight; and the movement sets the nerves in his shoulder spasming, slip-starting a chain reaction that jangles up his neck and down to the ends of his toes. This is more than just the regular ache of a nightmare. Something happened before he went to sleep.

Ignoring his protesting muscles, Dean hauls himself upright, digging his fingers into the bed. He swings his legs over the edge of the mattress; rests his feet on cold linoleum. He drops his head into his hands.

The Mark’s having a funny effect on him, of late. Not funny ha-ha. Funny freakish, horrible, disturbing. Every morning after… after the thing has acted up, Dean finds himself foggy and dizzy, groping ineffectually for memories of the previous day. So while it’s just about possible that the ache at the back of his head is simply a result of too many whiskies, that’s almost certainly wishful thinking. It’s been several years since Dean last got a hangover that way.

Dean rubs his fingers through the short hair at the back of his head and strains to remember what he did last night.

When he starts to see it, it’s in flashes; and it doesn’t take too many of those to make him regret that he tried. Black eyes in a startled face. The crunch of bone under his fist. A cloud of smoke – the damp warm wash of blood across the back of his hand – Sam trembling and determined, fingers around his wrist. Yeah, Dean remembers now, more than enough. A fight, and Sam had had to step in, to throw himself bodily between Dean and the guy he was beating. Sam’s mouth had been moving and he had been speaking but it had all been subsumed under the dull roar of the Mark in Dean’s ears. Dean’s not certain, but he’s pretty sure that he did his brother some serious damage before the thought of Cain’s warning had finally, somehow, clawed its way up to the surface of his brain.

So. Great. 

Dean drags his hands heavily forward, sliding them up the back of his aching shoulders, down over his collarbone and onto his chest. It doesn’t ease the pain; but he sits like that for a little while anyway, fingers notched at the base of his neck, left palm resting over his anti-possession tattoo. What a joke  _ that  _ turned out to be. Small good to put your body on lockdown, in a world where you can cook up a demon from your own insides.

Dean doesn’t want to move. He’s putting off the moment where he has to get up, walk back down the hallway into the library and see Sam’s face. He’s not ready, yet, to deal with the way that his brother flinches every time that Dean moves too fast: or worse, how Sam overcompensates for it by arranging himself self-consciously, conspicuously close at Dean’s side. It drives Dean crazy: Sam with his jaw and his shoulders set rigid in the front of the car, holding  himself stubbornly still as Dean leans over into his personal space. As an attempt at deception, it’s pathetic. Even with the Mark’s constant pounding clouding his head, it’s easy for Dean to see the little red crescents that Sam’s fingernails dig into his palms.

“I know what you’re doing,” Dean wants to say; wants to lean right up in Sam’s face and gnash his teeth, just to see his brother’s pupils dilate in fear. At the same time he wants to ruffle Sam’s hair, knock him on the shoulder, watch him smile. “I’m just your brother,” he wants to tell him. In fact, the Mark has tainted even that, loading the word with the iron-tang threat of Abel’s blood on the blade.

Fuck this, Dean thinks. He puts his hands on his knees and stands, pulling his boots straight onto his bare feet and shrugging a T-shirt over his head. He’s still wearing his jeans, which probably means he ought to change them; but it doesn’t seem worth it when all he wants to do is spend some time with the punching bag in the Bunker’s worn-out gym. Of course, it might be that even that counts as feeding the Mark: that he ought instead to be unrolling his yoga mat and following Sam into Downward Dog. But right now Dean wants to hit something pretty fucking hard, and the punch bag seems like a safer option than anything else.

He creaks open the door, half-expecting to find Sam’s sleeping body in the passage outside. It’s happened before; Sam unfolding his long limbs in startled guilt as the opening door woke him with a knock to the spine. Dean hadn’t been sure if Sam was acting as protector, or prison guard. Prodded for an answer, Sam had denied both; and Dean had found himself turning snappy and hostile, irritated by his brother’s oppressive, humiliating concern.

Tonight, the corridor is empty. But it isn’t quiet. There are voices echoing, bouncing off the tiles. Down in the library, Sam and Castiel are having a fight.

For an unexpected second, Dean finds himself thrown back to childhood, to his mother and father’s irregular fallings-out. This gives him the same odd feeling of the ground shifting beneath him. Despite the ‘profound bond’ he and Cas apparently share, the two of them just can’t seem to stop butting heads. Dean hasn’t got the patience for Castiel’s endless, stupid mistakes; for his bumbling and usually ineffectual goodwill. But it’s almost unheard of for  _ Sam  _ and Cas to argue like this. Lately, especially, they’ve been best buddies; texting surreptitiously behind Dean’s back, gathering to whisper their concerns where they think he can’t hear.

It’s been this way ever since last year, when Gadreel commandeered Sam’s body and Dean took on the Mark. Something that neither Sam nor Cas will discuss went down during those two weeks when Dean was away, before he and Sam crashed back into each other’s orbit on the hunt for Garth. Neither of them has told him what it was, and Dean hasn’t asked. He feels a certain amount of unfair jealousy that Sam turned to Cas after Dean walked out; when really, what else could the kid have done? And what else would Dean have wanted? Sam’s always needed  _ somebody  _ to hold his hand; if not Dean then Jessica, Ruby,  _ Amelia _ . Lately, that person seems to be Cas.

So, to hear them shouting like this? It shocks Dean, but it fascinates him, too. He slips off his boots and sidles barefoot down the corridor to listen in.

As he nears the library, it rapidly becomes clear that he’s behaving more cautiously than is really required. He must have been out for a while: long enough for the pair of them to have forgotten to worry about waking him up. They’re full-on yelling at this point, Sam’s voice in particular raised and angry, in a way Dean hasn’t heard it since… well, he can’t even think of when. There was a time when Sam was essentially a solid wall of muscle and rage. Neither’s true now. His brother’s thinned down and the anger seems to have thinned out, too, become pointed and (Dean’s gotta say) petty where it used to be blunt and big. Half the time, it feels like Sam is too tired to be angry at all.

Not tonight.

“Just when I think you’ve got a basic grasp on humanity, this happens,” Sam says, loud and solid and mad. “And it makes me realise that you’re such a  _ fucking  _ angel after all.” Whatever Dean’s suspicions, this isn’t a term of endearment; not the way that Sam’s saying it now.

“You’re wrong, Sam,” Castiel says: growly, low. It’s his Big Serious Angel Voice, the one he uses when he’s trying to puff himself up beyond the trenchcoat and the wrinkled tie. “You don’t know what you’re talking about.”

“Yeah, and whose fault is that?”

“This is for your own good.”

As Cas says it, Dean winces. Sam’s not wrong. Cas is still  _ way  _ off in his human relations if he thinks for a moment that he can shut Dean’s brother down with a phrase like that.

There’s a tense, furious silence. Dean pictures Sam, mouth pinched tight, colour rising on his cheeks. He edges a little closer to the library door.

Soon enough, Sam breaks the tension: breathless, outraged. “How dare you, Castiel? How dare you try and tell me what is for my own good? Don’t you think I’ve had  _ enough  _ of other people trying to make choices for me? Don’t you think that maybe, for once, it might be nice to let me take a fully informed decision?”

“No,” Cas says, flat. “I know you, Sam. You will do what you think is necessary, regardless of the implications. And this? This is not a good idea.”

“That’s it?” Sam asks. There is a dangerous softness to his voice.

“That’s it.”

A beat. Dean is anything but surprised to hear the clatter of an overturning chair. There are a couple of dry slaps, skin on skin; the heavy bump of Sam’s boot against wood. The table scrapes along the floor.

“Nnnngh,” says Sam. Another chair falls over.

Silence descends.

Dean cranes his neck towards the door. He can see light through the long crack between the hinges; but the angle’s wrong to figure out what’s happening inside. He peels his bare foot off the tiles, steps nearer; wonders if they’re sufficiently absorbed in one another to allow for him to take a quick peep around the door.

As he’s weighing the options: “Come in, Dean,” says Cas.

A hot prickle of embarrassment inches its way up Dean’s spine. He thinks, for a moment, about walking away; sprinting down the corridor into the gym, and denying that he ever was here. But Cas’s celestial Spidey sense probably precludes that as an option. Better to brazen it out.

He slaps on a smirk, and swaggers in.

Cas has Sam pinned backward over a library table, straddling his hips with a hand around his throat and another trapping Sam’s arms together against the polished wood surface. Sam’s long legs are awkwardly folded beneath him, the table digging into his back. The whole position looks disconcertingly intimate.

“Uh,” Dean says, articulately. Sam’s eyes flick toward him. There’s a deep pink-purple bruise on his brother’s cheek, blossoming over the cheekbone under his left eye. It’s too ripe for Cas to have inflicted it in the moment’s scuffle: and the Mark twitches with interest when Dean looks at it, leaving him with the sick, certain feeling that the thing is his fault. There are more bruises – smaller, finger-sized – on the white wrists exposed where Cas has Sam pinned.

Swallowing the gut-punch, Dean tries again. “Don’t let me interrupt you lovebirds.” He’s aiming for a casual tone. “Just… you know. Keep the domestics to a minimum, if you want the kids to stay in bed.”

Cas frowns. (When doesn’t Cas frown?) He looks down at Sam.

“Will you stop attacking me?” he asks.

Sam nods, as much as he’s able with Cas’s hand at his neck; and Cas lets go, shifts backward to stand on his feet. Sam crumples at the knees, slumps onto the floor. He clutches at his throat and wheezes. 

Dean strides towards his brother, offers a hand. Hesitating a microsecond too long, Sam takes it, letting Dean haul him up onto his feet.

“Thanks, man,” he says, backing away.

With his fingers still warm from Sam’s, Dean glances at Castiel’s implacable expression. The Mark is blazing on his arm and he has to tighten his muscles fast and close to avoid pounding hard into Cas’s face. How dare he twist Sam up like that? Doesn’t he know about the kid’s bad back? Can’t he see the goddamn bruising all over him?  _ Nobody  _ gets to hurt Sam. (Nobody but Dean.)

“Dean?” says Sam, low – and Dean realises that he’s been looming, curling his fingers into a fist as he frowns. He deflates a little, relaxes his hand and tries to smile; although he’s not sure how many of his features are on board with the movement. Judging by Sam’s reaction, the overall effect is less than soothing.

Dean pushes through it. “Tell me, Sammy, what’s up?”

He figures the odds of his getting a truthful reply at somewhere around forty thousand to one. Sure, Sam might be feeling frustrated at his inability to get a straight answer out of Cas. But it’s been a long, long time since Dean’s brother felt able to let him in on his most secret plans: Sam’s too well conditioned, too hedged around by guilt, to ‘fess up about something that is obviously sketchy as fuck. So Dean watches without many expectations, as Sam sucks at the inside of his cheek and looks down at his hands.

Eventually, though, something hardens around his jaw; and he looks up, looks Dean in the eye.

“It’s Lucifer,” he says.

Five years ago, when Sam called Dean up from the other side of the country and told him that Lucifer was planning to ride him over the backs of the world, Dean had been too beat-down and worn-out to care. Sam, the Sam he’d loved and coddled and protected, was gone; and the new strange man who’d greeted him after he got back from Hell had sold out everything Dean went down for to chase after some demon bitch and feed himself sick on her blood. Screw the apocalypse. That fight in a North Dakota honeymoon suite had already felt like the end of all things. Sam’s departure, weeks later, had been only the belated flick of a switch, the pulling of a merciful plug on a patient who had long been dead; and when Dean got that call, he hadn’t wanted to revive the corpse. “Pick a hemisphere,” he’d told his brother; and hung up the phone.

Zachariah’s trip to the future might have prompted them back together, but Dean’s not sure that they ever really fixed what broke back then. So, this time, when Sam says ‘Lucifer’, he’s certainly not short on emotion. But he bites down the instinctive, angry response: there’s no sense scaring Sam into silence before he’s even spilled.

Instead, he keeps it clinical. “What do you mean?” he says.

Sam twists his index finger so hard that Dean thinks it might break. He takes a deep breath.

“Metatron said. I mean. You remember what Metatron said about finding the source?”

“Yes,” Dean says. This is it? “We  _ found  _ the source, Sam, you might remember. And I killed him.” If Sam’s forgotten it, Dean certainly hasn’t: a dark night in a dark barn that left Dean feeling like the last remnants of hope had been squeezed from his soul.

But his brother’s shaking his head. “Not Cain. Cain got the Mark from Lucifer. You remember?”

Dean nods.

“So, we, uh… we saw Metatron again, a little while ago” – and when the fuck did  _ that  _ happen, Sam? – “and he said that he’d made up the thing about the source. But he also… he mentioned Lucifer, too. It was Lucifer who created the Mark, Dean. If anybody can take it off…”

Dean bites down, hard, on his own lip. He tastes copper. “And this is what Cas won’t tell you?”

Sam spreads his hands, desperate, appealing. “He has an idea. I  _ saw  _ him have it, he found something and he won’t tell me and… I just want to know. I just want to understand what our options are.”

_ No _ , Dean thinks, and he’s not exactly sure where it came from. It  _ feels  _ like it’s him; but there’s a tension, also, somewhere in the back of his brain. Before he can analyse the thought, his mouth is open and he’s pushing Sam back with the same half-responses he’s been using now for months.

“How many times do we gotta have this conversation, Sam?” he says. “I’ve told you to drop it like a thousand times by now.  _ We  _ don’t have  _ options _ . This isn’t something you can solve. It’s something I have to handle. My problem. My choice. And what I’ve  _ chosen  _ to do is to deal with this for as long as I can. I thought you were on board with that.”

“No,” Sam says. It’s unusual enough to make Dean double take. “No. You’re not dealing with it at all. You’re just waiting around for… for I don’t know what, because it won’t be death, not with that thing on your arm. It has to  _ go _ , Dean. And this could be the answer, something real.”

Somewhere very deep down inside himself, Dean begins to feel a tiny, germinating sprout of belief. It’s dangerous. Hope is what gets you hurt. But looking at Sam’s pleading expression, the forehead and the big damp eyes, and remembering somewhere through the fog of the Mark that they have, haven’t they? They’ve always managed to do it before… He finds something, just enough of a thread to be worth holding onto for a little while longer.

“OK,” he says. “OK.” And he wheels around to face Castiel, who has been looking at them all this while with an expression of profound consternation. “Sammy’s right. Let’s hear it, Cas.”

Cas shakes his head. “As I have told Sam,” he says, “I don’t think that this is a suitable solution.”

“Not really your call, Cas,” Dean says; and he knows, as he says it, that Castiel will be persuaded: that he’s never been able, in the end, to refuse Dean anything that he really wants. But Cas is trying to be adamant, shaking his head; and Dean doesn’t have the patience for a drawn-out battle. Instead he thinks,  _ OK. I can do this. I can do this for Sam. _ And he lets it go, just for a moment, takes off the reins and lets the black nastiness that’s been nipping at the edges of his mind surge suddenly to the fore. It’s easy to do, easy to sink down into it; a helluva lot harder to get out. 

When he resurfaces, maybe sixty seconds later, it seems like not much has changed. Cas’s shirt is rumpled (more rumpled than usual), and he’s breathing heavily, and Dean’s knuckles are stinging. But the real shock is in Sam. He hasn’t moved. But his eyes have the wild look of a horse about to bolt, and his limbs are taut with a painful, quivering suspense.

“It’s OK,” Sam says to Cas. His mouth shapes the words, but the sound isn’t there.

Cas looks at Dean’s brother. “Enough,” he says. “Enough. I will tell you what I know.”


	2. Chapter 2

“I will tell you,” Cas says, gazing with extreme solemnity at Sam. “But please, remember my objections.”

“Yeah, yeah,” says Dean, impatient. Sam’s face by contrast is serious, set, his eyes directed somewhere around Cas’s knees.

“I think it likely,” Cas says slowly, “that there are traces of Lucifer’s grace still left in Sam.”

“Say what?” says Dean.

There’s a heavy silence before Sam speaks. When he does, it’s like Dean’s not there. “You don’t  _ think it likely, _ ” he says in a small, tight voice. “You  _ know _ .”

He lifts his head, and his face is white; nostrils flaring, lip trembling just the tiniest bit. “You must. I mean. When… Gadreel. You saw what he’d left in me. You must have seen… the other thing, too.”

Cas looks shifty.

“It didn’t seem helpful to share that information,” he says.

Sam closes his eyes, swallows. “Right,” he says. “My mistake, I guess.”

Aggravated, excluded, Dean speaks up. “Back up a second, would you?” he says. “I’m missing something here.”

Sam looks up at him, looks away, the set of his shoulders tense. Dean watches Sam’s fingers curl over the edge of the table, watches the muscles in his forearms flex as his fingers tighten, notices the vulnerable bulge of his brother’s veins.

Eventually, Cas speaks. “When an angel takes a vessel,” he says deliberately, “they suffuse it” – Sam coughs – “they suffuse  _ him _ , with their grace. It’s the life force that bends the vessel to the angel’s will.”

“Yeah, yeah,” Dean says. “I know all this.”

“Well,” says Cas. “Depending on the length and the intensity of the possession, traces of that grace can remain after the angel departs.”

Dean has heard this before, or something like it, something raised and rapidly dismissed by Sam after that godawful mess with Gadreel. Hearing it now in this new context, the shock of what Cas is saying hits him like a slap. All these years that Sam’s been back and been sitting beside him, he’s had the thin scum of the devil lining his veins.

“Jesus, Sammy,” he says. “Use a condom next time, would you?”

It’s a reflex, more than anything: this is how Dean deals, make a lewd joke about the horror and move on. It’s only when Castiel –  _ Castiel _ – looks at him with a horrified frown that Dean thinks, maybe that wasn’t cool. He sneaks a glance at Sam; but his brother’s hair is falling over his face so that Dean can’t see his expression at all.

For a long moment, Sam doesn’t speak. His chest rises, falls. Dean thinks idly about puncturing Sam’s lungs, letting the air wheeze out of them, flat balloons.

Eventually, Sam stands up. “Excuse me for a moment,” he says. His mouth is careful around the words.

Dean watches as Sam walks, very cautious and deliberate, away from the table. His steps speed up when he gets to the doorway and he makes it as far as the sink in the war room before he hurls. Sam vomits in loud, choking coughs, long back hunched over, hands gripping the porcelain. 

Dean knows that he ought to go and comfort his brother right now. He should smooth his hands over Sam’s shoulders and down the ridge of his spine; talk to him in soothing words, rub circles at the base of his back. He wants to do all these things. He also wants to stalk over on purposeful feet, take Sam by the scruff of his neck and slam Sam’s forehead into the mirror in front of him. The image is vivid: cracks hurrying across the glass, blood running into Sam’s eyes.

Dean sits tight.

Sam finishes, spluttering down into silence. He turns on the tap; bends down further to drink. He keeps the water running after he stands, and Dean pictures it, chunks of Sam’s stomach lining circling the drain. He feels kinda queasy himself. 

Sam straightens up. He doesn’t look into the mirror. Instead, he tosses his head, rubs his hand over his mouth. He walks back into the library.

“OK,” he says.

“Sam –” says Dean; but Sam ignores him, looking only at Cas.

“How do we do this?” he says. “What - back into the archives for the king-sized syringe?”

“Not in this instance,” says Castiel. “We can’t use that procedure this time. It’s not suitable.”

Sam’s eyebrows lift in surprise; and his mouth drops open, just a little. The expression turns him suddenly childish, draining off the weight of the years and the worry that can make Sam, glimpsed out of the corner of an eye, look like a hunched old man.

“What? Why not?” he says.

Cas’s eyes trail over to Dean with some anxiety before they return to fix on Sam’s face. “You remember, back then,” he says. “We could not recover enough of Gadreel’s grace to be useful.”

Sam nods, small.

“The grace that Lucifer left in you,” Cas says. “It will have… it’s lodged deeper. So it would be harder to extract.”

“Right,” Sam says.

“I don’t think we could do it without killing you,” Castiel says, suddenly honest. “It was unpleasant enough last time.”

Sam’s tongue flicks out pink to moisten his lips. “Yeah,” he says. He looks exhausted. “What, then?”

Last time? It’s a revelation, a peek into the secret weeks that Dean’s been mulling over for months. And yeah, Dean should be – he kind of  _ is _ – retrospectively concerned for what might have been. But he’s also furious with his brother for keeping this quiet, for hiding the fact that he almost died after Dean compromised so much to save him. How could Sam do that? Yeah. Dean’s straight-up mad with him for lying. And somewhere mixed in with that familiar feeling is a darker resentment, at the fact that Sam might just have walked out on the world when Dean wasn’t there to see.

“I’m not altogether certain, yet,” says Cas. “I think it might be -” he pauses, looks apologetic - “I think it might be necessary to channel Lucifer’s power through a vessel. A human vessel. Through you.”

It’s like watching Sam get beat down by a ghost: the shock and absorption of a series of invisible blows, striking him in the solar plexus, brutally, one by one. You’d think he must have seen this particular punch coming, but the impact of it still manages to elicit a physical flinch. Sam reels; and Dean suddenly can’t stand to see any more, feels sweaty with disgust at the whole situation. He told Cas to say this, sure. But he doesn't have to like it. 

“Gee,” he says. “A lot of good that does. Tell Sam he has to fuckin’ spread ‘em for Lucifer and go light on the rest of the details? What are we actually supposed to  _ do _ ?”

“The answers most probably lie within your library,” Cas tells him, calm. “When Sam and I were seeking Gadreel, we found the Men of Letters to be impressively well informed. It’s just that I have been restricted until now, because I was hoping to prevent Sam from following my investigations. But it ought to be possible to find the necessary information here.”

Dean looks at his brother. Sam is nodding.

“Fine,” Sam says. “I’m in. But Cas. I want to make sure that we get it right first time. So please, please, make sure that the research is solid. I don’t want to be doing this twice.”

Cas inclines his head.

“I’ll help you look,” Sam says. “Later. But I think,” and with the words he seems to slough off the final remnants of the front that he’s been carefully clinging to all this while, shedding them like a worn-out skin to show his insides exposed and raw, “I think that right now I need to go to bed.” He looks at Dean through red-rimmed eyes. “I’ve been up for, like, thirty hours.”

“Thirty-two,” says Castiel.

“Right,” Sam says. “Whatever. I’m just… I’m no good when I’m this tired.”

“It’s OK, Sam,” Dean says. “I can do it. I can help him out.”

Sam closes his eyes, nods again, then turns and shuffles out of the door. Dean watches him, the defeated line of his shoulders.  _ Come on, Sam _ , he thinks.  _ At least put up a fight. _

Of course, Sam knows more and better than Dean about the Bunker’s stores. He’s the one who’s spent half his life in libraries; who understands about archival systems and classifications, who gets a kick out of using the ancient card catalogue and who dug up a typewriter from some long-abandoned office in order to add his own notes in kind. But Dean’s not stupid, and more importantly, he knows how Sam works. He’s picked up more than enough to help Castiel out on his quest.

So the two of them walk down together to the archive, a great suite of rooms on the second basement level, underneath the regular parts of the Bunker where they actually live. Dean’s been down here several times since he took on the Mark, poking around the Men of Letters’ records on curses and scars. For a while, though, now, he’s put the search on hold; so the mouldering coffee cups he finds slotted randomly into the shelves must be evidence of Sam’s continued, isolated labours.

Dean looks at the one closest to his eyeline, a bright green thing with a chip in the rim and the faded logo of a Florida waterpark on the side. For a second he considers hooking a finger into the handle and flicking the mug onto the floor just to watch it smash. But he catches Castiel’s blue gaze from the corner of his eye, and restrains his hand.

“Right, then,” Dean says. “Angels.” And they both dive in.

As they search, leafing through books and portfolios, reaching down dusty archive boxes and poking through what’s within, Dean keeps thinking about what he’s just heard. 

“Cas,” he says. “This thing with the syringe and Gadreel’s grace.”

Cas puts down the folder in his hand and gives Dean his full attention.

“Did Sam really nearly die?”

“Oh, yes,” says Castiel. “He was quite determined. I believe that he felt it would compensate for Kevin’s death at his hands.”

Dean feels an odd, proprietary outrage. “What the fuck?” he says. “Kevin’s death was on  _ me _ .”

Castiel regards him, level. “Nonetheless. Sam felt considerable guilt about what happened. He seemed to believe that finding and killing Gadreel would offer some measure of redemption. But I advised him otherwise.”

“You advised him,” Dean says.

“I told him,” says Castiel, “that I understand what it is to make mistakes. But that however many mistakes he might have made, death was not the right or suitable solution.”

Something about this doesn’t quite sit right. Kevin’s death is  _ Dean’s  _ problem: Dean’s mistake. Dean knows that, because that guilt is his justification for this whole, messy business with the Mark of Cain. He had to take the damn thing on to kill Abaddon – no, to kill Gadreel. Or something. To do something good, at any rate, that would make up for his terrible error. So what exactly did Sam think he was doing, trying to sacrifice himself instead?

He looks at Castiel’s complacent face, full of pride at his achievement in persuading Sam that suicide would simply be another sin on the list; and he feels so terribly tired at the prospect of untangling that particular cat’s cradle that he just doesn’t bother.

“OK,” he says. “Well, thanks.”

Cas nods, and gets back to his documents; and Dean wanders off to the other corner of the room, starts to go through the older boxes from even longer ago. As he looks through the folders, he thinks: what if Cas had done it? What if he’d pushed on through and pulled the stuff out and let Sam be damned in the process? Dean had already taken on the Mark by then; probably picked it up around the same time that Sam and Castiel were arguing over Sam’s life. Without his little brother beside him, where would he be right now? The answer feels painfully obvious: slumped next to Crowley on their ongoing demon bender; or worse, snug-tight in the bastard’s throne, the newest ruler of Hell. Both are possible. It’s felt many times this past year like Sam’s deceptively steely grip is the only thing holding him back from the abyss. Trouble is, sometimes Dean actively wants to jump into it. The fall would hurt, but it feels like it might be simpler than this constant, nerve-wracking teetering on the edge.

He’s done; so done, and yet he’s somehow been persuaded, by the power of Sam’s stupid kicked-animal eyes, into making a last dragging venture towards salvation. So, he supposes, the least he can do is to give it a go. He sighs, deep in his chest, and starts scanning the files.

~~~

Dean’s never been the most enthusiastic researcher; but he’s usually at least efficient by necessity, sorting things through quick and thorough so he doesn’t have to look at them twice. Today, though, he’s not on his game. Every page he turns seems to lead him astray, so that he finds himself staring for twenty minutes at a tedious treatise on archangel genealogy, words running meaningless in his mind, before he snaps awake. Jesus. His brain just won’t do what he wants it to; there’s some hovering force at the back of it, tugging his thoughts off track. It’s like every page that he’s reading is written in Latin: he can make his way through it, but the task is arduous, slow. 

He puts his hand to his forearm without thinking, but when he realises where it’s settled, he knows that his answer’s there too. Of course. The thing doesn’t  _ want _ to be removed. This is just another obstacle in his way.

The recognition nudges at Dean’s more obstinate instincts, prompting him into a renewed burst of activity; and, maybe five or six books later, he finds himself holding exactly the text that he’s sought.  _ Harnessing an angel’s residual energy, _ reads the heading:  _ Necessary preparations for the vessel, body and mind.  _ Dean reads on. The book is old and sturdy, backed in leather with the imprint of the Men of Letters stamped onto the front; and it’s written in a stiff kind of formal English that Dean suspects is as much the product of deliberate archaism as it is a function of the time that the book first appeared. This is the work of a learned society self-conscious of its own, authenticating tradition.

Whatever, Dean scoffs. What matters is what it says. Pompous old dudes and their fusty phrasing be damned; he’s got his hands at long-fucking-last on the key to his own release.

But as his eyes pan down the page, he begins to realise with a sinking feeling that Castiel was right. No. No way. Whatever Sam might feel about the way that Dean’s been behaving, whatever crazy ideas he’s got in his head about what might happen next, there’s not a chance in Hell that Dean can ask his brother to do this; that he can ask Sam to do this to himself, for him. No. No. It’s not going to happen.

Over at the other side of the room, Castiel calls out to him, “Dean? How’s it going?”

“Still looking,” Dean calls back. He casts a quick, guilty glance over to the shelves behind which Cas is concealed, then picks up the volume he’s holding and shoves it awkwardly into his shirt. “I’m just gonna go and use the bathroom, alright?”

“Of course,” Cas says. “Your toilet habits are none of my business.”

“Yeah, OK, thanks,” says Dean, already halfway out of the door with the book poking an accusatory corner into his chest. He’s overtaken with the horror of what he’s read and with the absolute dread certainty that nothing will stop Sam now: that even if it means subjecting his fragile mental stability to a final, shattering, sledge-hammer blow, Sam will do it to save Dean’s soul and not think twice about the action. It can’t happen, mustn’t happen. Dean won’t let him even consider it.

Almost without consciously deciding to do it, he’s pounding up the stairs into the bunker’s largest washroom and setting the book down carefully in the middle of the white-tiled floor. It’s as good a place as any, and he gropes with slippery, sweaty fingers in his pockets for a lighter or match. “Come on,” he finds himself chanting under his breath, gasping with relief when he finally settles his hands on the metal of a Zippo. “Come on, come on.”

The room is dry and so is the book but the leather of the cover proves unexpectedly tough. Dean’s thumb goes numb with clicking at the flint before he's finally able to kindle a lasting flame: and even then, it flickers useless against the binding for the longest time. “Fuck,” Dean murmurs, and drops the book open, leafing through to the offending section. This is the only part that he really needs to destroy; and thankfully, this time, the flame catches and a thin black border of burning creeps quickly around the edge of the page. 

Dean’s watching it, heart in his mouth, when suddenly he’s propelled sideways across the bathroom, shoulder and hip slamming painfully into the wall. In the centre of the room, Cas snatches up the burning volume, smothering the flames against his coat. He looks at Dean, face set and angry. 

“ _ No, _ ” he says.

Disoriented and incredulous, Dean’s not immediately able to articulate his outrage. “What the fuck?” he splutters at last.

“You were trying to destroy it,” says Cas. “The answer. The way to get rid of the Mark.”

“Christ’s sake, Cas,” Dean says. “You don’t understand. Sam can’t – it’s not a good solution.”

Cas watches him, silent.

“You were trying to hide the whole thing from him yourself!”

"I was wrong," Cas says; and is he really stupid enough to think it's that easy? That you can just make a mistake and change your mind and move on? “Sam was right. Things have gone far enough, Dean, and we need to find a way to help you.”

“This isn’t about me, not now,” says Dean. “This is about Sam. You don’t get it, Cas, you don’t know –”

Cas interrupts him. “I’m not stupid, Dean. I know what it says.”

“Well, then,” says Dean, although Castiel’s unshaken assurance has jolted some of his certainty. “You know that Sam’s not strong enough. I don’t know how – I mean. Jesus, Cas, you were the one so down on the whole thing first time round. Called him a fucking abomination, if I remember right.”

“I was wrong then, too,” Castiel says. “Sam is stronger and better than I gave him credit for. And you are wrong now about your own reasons for acting. Think about it, Dean. Why did Cain kill his brother?”

This is something that Cas must have picked up from Sam: the condescending, infuriating ability to be  _ right _ , to present a point that Dean can’t answer and which frogmarches him by sheer force of logic to some unpleasant philosophical place in which he really doesn’t want to end up. It’s his least fucking favourite of Sam’s behaviours and the fact that Cas has now started in on it is ten times worse. But the son of a bitch is right, and so Dean grits his teeth and grinds it out.

“Cain killed Abel to save him. From Lucifer. He killed him so that Lucifer wouldn’t corrupt him.”

Cas doesn’t need to say anything more. It’s enough that he’s muddied the waters: that he’s clouded Dean’s confident clarity into the same murky self-suspicion that has hindered every step of his action since the end of the summer, since the moment when Sam bound him down in service of that half-assed cure. Because yes, when Cain first explained his actions, standing in the kitchen of his cottage with a rational smile, Dean had understood exactly the impulse that had driven the guy’s desperate slide into damnation: had recognised the absolute imperative to preserve the purity of a little brother with a soul a hundred times more precious than your own. But now. After his most recent face-off with the Father of Murder, Dean’s been somewhat less sure about how things went down. Cain had seemed frighteningly unfazed at the prospect of murdering some innocent kid, just on the off-chance that he might turn bad. Who’s to say that the guy’s first step wasn’t similarly suspect: that it wasn’t  _ him _ being taken for a fool all along?

Dean’s not convinced either way. He certainly hasn’t articulated his suspicions to Castiel, still less to Sam. But he’s just not sure  _ enough  _ that Cain’s fratricide was an act of mercy, rather than a murder that the devil endorsed. 

Castiel watches him waver, and tells him, “Go and talk to Sam. And be honest. You owe him that.”

~~~

Dean leaves Sam to sleep for as long as he can bear it; busies himself for a good five or six hours to give the kid some chance to rest. Sam’ll need all the strength he can get to handle what Dean has to tell him. But the waiting is torture. He paces up and down every one of the bunker’s corridors; beats three punching bags until they’re leaking stuffing; makes himself an elaborate, disgustingly healthy breakfast; and even, driven to desperation, goes out on a run. Eventually, when he can’t take any more of it, when the Impala is shining and the kitchen is gleaming and he’s taken every gun he owns to pieces and put them back together, he knocks, ever so gently, at the door of Sam’s room.

“Come in,” says Sam. When Dean does, he sees his brother sitting at the head of his bed, back against the wall, forehead resting on his drawn-up knees. He’s wearing the same clothes that he had on when Dean last saw him. Dean’s pretty sure that he hasn’t even shut his eyes; or if he has, it’s been the kind of shitty, fitful dozing that leaves you worse off than when you first lay down. 

Sam must have heard the opening door, but he doesn’t move. He doesn’t even stir until Dean’s close up beside him, awkwardly clearing his throat. And when Sam does look up, it isn’t pretty. His face is oatmeal grey, and there are heavy dark circles under his eyes. He looks like shit. 

“Come on then,” Sam says. “Let me have it.”

Dean opens his mouth, but there’s something heavy and tight around his chest that stops him from speaking. He’s gone over the sentence dozens of times, pounding out the words with his alternating feet as he powered through the woods outside. But now, now he’s there in the room with his brother, he doesn’t want to say it; and he surprises himself with what happens instead.

“What I said earlier,” he tells Sam. “About. About Lucifer. About what happened in the Cage.”

Sam’s head snaps up. The whites stand out around his eyes. “Dean,” he says, warning.

“This is important,” Dean says. “Did he. Did he. Or. I mean. Sam, I know what can happen in Hell.”

Sam is mute.

“Dude,” Dean says. “What I said. I was making a joke about possession. I wasn’t. Fuck, man. I just didn’t think. I was talking about possession, OK?”

Sam looks at him for the longest time, before at last he closes his eyes and massages his fingers across them. “Come on, Dean. You know as well as I do, it’s the same damn thing.” His voice is explanatory; it’s not unkind. But it coaxes a thick, nasty bile from the back of Dean’s throat.

Time passes. Sam breathes in, deep. Dean explores the black bitter taste in his mouth with his tongue.

At last, Sam opens his eyes and asks, false and bright, “Anyway. Is that all you wanted to say?”

“No,” Dean says, hating it. “No. It’s. Um. I think we found what we need, or most of it. About how to use Lucifer’s grace.”

Sam waits; and Dean, reluctant, miserable, drags his gaze heavily Sam-ward.

“It’s,” he says; and chokes on it. “You’re gonna. Oh,  _ Sammy,” _ he says.

He really thinks that he’s going to have to say it: but it turns out, Sam’s too fucking smart of a guy to have missed the obvious, and too fucking merciful to let Dean suffer the way he deserves. Instead he gives a horrible, papery laugh and offers Dean the words already, again, on his own account.

“Demon blood,” he says, looking carefully past Dean’s midriff to the blank bare brick of the wall.

“I’m sorry,” says Dean, “so fucking sorry,” and, “please, Sam, don’t do it.”

Sam does look up then, and his face is twisted in something like cruelty, or pain. “Fuck off, Dean,” he says.

“I mean it,” Dean tells him. “It’s not worth it for you.”

Sam smiles, sort of. He lifts a hand to the back of his head, curls his fingers into his hair and tugs at it, hard. “I don’t really understand what you think the alternative is,” he says.

Dean opens his mouth; closes it. He’s coming up dry.

“You’re going to kill me, Dean,” Sam says, eventually.

And all Dean can say is, “I think I am.”

 


	3. Chapter 3

Dean doesn’t expect to sleep that night, but he does. He dreams of Sam in a white suit with glowing white eyes, feels the comforting solidity of the First Blade in his fist, and watches the demon fizzle out of his brother’s mouth as he plunges the teeth of it deep into Sam’s belly.

“Thank you, Dean,” Sam says; and dies.

When he wakes up Dean sees Sam, alive, standing in his open doorway with the familiar crease of wrinkles across his forehead. He throws Dean’s empty duffel at his head.

“Heading out,” Sam says, short and firm, like since the night before he’s pressed a pencil hard over the fading lines of himself, become something sharper and tougher and more clearly defined.

Dean should have expected this: Sam’s always been one for action, doesn’t like sitting and waiting around when there’s a job to be done. He remembers how it was during the Trials, even (no, especially) when Sam was at his weakest, feverish and shaking, bones rising through his dwindling flesh. The whittling back of Sam’s body had been painful enough to witness, but for Sam the real source of agony had been Kevin’s slow progress on the tablets’ translation; the waiting had kept him constantly fretting and jittery, burning too fast through his picked-over morsels of food. If Sam has something horrible to do then he likes to just do it, flat out, just mans up and squares his shoulders and takes the worst on the chin. Dean’s seen it, over and again: seen Sam grit his teeth and stick his hand into a monster’s heaving guts, seen him set his jaw and point his gun and shoot a weeping girl he was half in love with. It’s admirable, Dean supposes, but he doesn’t always like it: finds himself obscurely resentful, like Sam’s ability to put his head down and grit on is some kind of criticism of Dean’s own strategy; suppress, deny, and hope things work out better than they ought to. So far neither of them is really coming up trumps.

Anyway, this is turning into Sam’s gig, and Dean obediently begins filling the bag. He’s a pretty well-practised packer by now, so the process takes maybe ten minutes, max, but by the time he makes it out into the central hall Sam’s already antsy, itching to go.

“I came as fast as I could,” Dean says, although Sam hasn’t voiced a criticism.

“I know,” Sam says, already heading upstairs.

When Dean gets up into the sunlight he finds Cas sitting quiet in the back of the car. Sam’s standing beside it, wavering a little, but Dean strides confident over to the driver’s door, slides right in. Of course he’s driving. He always drives.

He has his hands on the wheel before he realises. “Where are we going?” he says.

Sam’s tone is carefully level. “Ilchester, Maryland. I thought, if we go straight on Route 36 across to Hannibal -”

“Wait,” Dean says. “Ilchester.”

“Yes,” says Sam. Somebody who knew him less well than Dean might miss the strain in his voice.

Cas breaks in. “I was concerned about the strength of what remnant of Lucifer’s power might still be left in Sam. This location, where he broke through once before, should help to reinforce the spell.”

It could have been worse, Dean supposes; it could have been Stull. Even his current, intermittently emotional state, he’s not sure that he could face going back to that spot, the place where he’d dug his fingernails raw, clawing at the ground that had so dispassionately swallowed Sam up. But at least the cemetery is in Kansas, just a few hours away. Ilchester is more than a day’s solid travel.

Dean’s tried out a lot of metaphors for the Mark and how it works: it’s a brand, a burden, a drug. Here’s another: it’s a catalyst, an alchemical reactor that turns everything he feels, every strong emotion, into rage. There are a lot of things he might feel about going back to Ilchester, the place where Sam killed Lilith and broke the seal that set Lucifer free. He might feel pain, horror, misery. Frustration. Regret. The thing on his arm swallows up all of this, greedily, chews on the sensations and spits them back out as a thick fury that threatens to consume him, numbing him to anything else.

He breathes deeply, struggles to keep calm. But he’s barely pulled the Impala out onto the road when he finds himself blinded by a lightning vision of the car smashed sideways into a tree, Sam’s forehead mushy against the dash. It’s beautiful. It’s sick.

Struck sideways by the vivid heavy metal scent of blood, Dean slams hard on the brakes; and Sam has to shoot out a hand to stop himself going head-first into the window for real. Sam doesn’t say anything, though. Instead, they sit there, all three of them, in the stopped car maybe 100 yards from the bunker’s door.

Eventually, “What’s happening?” says Cas.

“Sam’s driving,” Dean manages to choke out. The Mark sends a sharp, punishing shock of pain through his arm; but he ignores it, fumbles open the door and staggers round to the passenger side. Sam slides compliantly along the seat. He lifts his hands to the wheel, shakes the hair out of his eyes. He clears his throat.

There’s another beat of uncomfortable silence before he starts the car.

~~~

Sam and Cas kill the demons outside Normal, Illinois; fast and efficient, in and out, four bodies drained dry and left at the side of the road. They leave Dean in the car, as if he were a child; and he remembers Sam, maybe ten or twelve years old, wrapped in a blanket in the back of the Impala and parked way out in the woods while Dean and Dad were chasing something big. It didn’t happen often, of course; better to leave Sam back at the motel or the house, doing his homework and cooking his dinner and tucking himself into bed. But sometimes, if the money was running low, there was no other way. Dad would give Sam a gun and tell him to leave the lights out and hunker down in the dark. “Get some sleep,” he’d say: but every time they got back to the car, however late, it had been to find Sam white-faced and open-eyed, staring out into the night.

Left waiting while Sam and Cas execute their executions, Dean shouldn’t be scared. He’s not a kid, but a full-grown man: not a skinny adolescent jumbling worries about werewolves with anxiety about outgrowing his sneakers and fitting in at the latest school, but a hunter scarred to toughness through Purgatory and Hell. Still, there’s something inherently disconcerting about being left out here in the dark. He knows, of course, why they’ve done it. They don’t want to set him off, don’t want to start the avalanche when they’re never quite sure it will stop. He’s tried to tell them that killing helps, although he’s not actually sure that’s true. It keeps his mind clear, at least, delivers a welcome focus that helps him to block out the whispers and the fear, distracting from the constant thirst for Sam’s screams.

Out here in the car by himself, there’s nothing else to think about; so Dean falls to mulling things over, worrying at the cracks in this so-shaky plan until they seem to split wide open. Sam’s strong. That’s what Cas has said. Sam is stronger than Dean gives him credit for, and Lucifer won’t take hold. It’s probably true. It might be true. Sam did it before. But then… Dean doesn’t want to think it, but out here, there’s nobody to lie for. Last time, Sam took hold of the devil _for Dean_. It was them, the two of them, the link between them, that helped Sam to find his way back. Nowadays, that’s looking like a pretty frayed fucking thread to hang all their hopes on.

It doesn’t help that when Sam comes back, he has blood up to his elbows, a smudged thumbprint of red on his lip, and is wearing a focused, almost feral expression that throws Dean immediately back into those terrible months when he could see Sam lying every day and couldn’t do a thing to stop it.

“Did you….?” says Dean, looking at Sam’s mouth, and Sam scrubs the smear away with the hem of his coat. He leaves red fingerprints on the fabric where it’s touched his hand.

“Cas said I should start now,” he says. “With a little bit. Or my body might reject it.”

“I thought it was in you all the time,” Dean says.

Sam opens his mouth; closes it. “I’ll drive this next bit,” he says, eventually. “You need to sleep.”

Sam scrubs his hands on the seat of his pants before he touches the steering wheel, but it only does so much, and Dean can’t help staring at the red-brown stains that still outline his knuckles and nails. Sam doesn’t say anything, doesn’t show that he’s noticed, until he pulls off the road by a dilapidated gas station.

“Bathroom break,” he says.

When he comes back to the Impala, his hands are pink and raw, and the chalky scene of cheap soap filters up slowly until it’s filling the car. It’s pungent, persistent enough that Dean can still feel the edge of it at the back of his throat ten hours later, when they hit the Maryland state border and he retakes the wheel from Sam.

~~~

“The thing about demon blood,” Sam says, “is that it’s also… blood.”

He looks at the mess in front of them, big empty lot, weeds already growing through the concrete cracks. This is where the convent used to be. Dean turns his head, too, standing silent by Sam’s side. He remembers the terror that he felt that night; the desperation and the panic as Cas finally let him free and he pounded through the night to stop Sam starting the end of the world.

“Okay,” says Dean.

“What I mean,” Sam says, “is that it comes from… it’s the same blood that belongs to the vessel. Right? It’s human blood, it was human blood once. Only the demon does something to it, turns it, fucking... transubstantiates it into this other thing. But I’m still drinking human blood.”

Dean thinks about it. He’s not sure that he understands the horror Sam’s evidently struggling with on this point. People exchange bodily fluids. That happens. It’s the demoniacal part of the bargain that Dean finds problematic. Mostly.

“You’re a vampire, Sam,” says Sam. He’s smiling, but the corner of his mouth tugs down. He pauses. It’s like he’s quoting a line from a movie; like he’s waiting for Dean to join in. But Dean doesn’t understand the reference.

“… A bloodsucking freak,” Sam supplies.

Dean frowns. “I don’t…”

“Don’t worry about it,” Sam says. “Not worth remembering.” He turns to pick up the blood, big plastic jugs of it set in the trunk of the car just like the last time Sam chugged himself powerful and went off to let Lucifer in. For a moment he stands there, his back toward Dean, hand resting on the handle of one of the bigger containers. It’s a long moment before he grips it properly with his fingers, screws off the cap with his other hand, and lifts.

This time he doesn’t ask Dean to turn away.

Dean watches the volume of the liquid dwindle, thinks about the thick viscosity of it running down Sam’s throat. He understands blood-hunger, now; understands the draw of it, the thrum of the need in his veins. But Sam the addict is something that still fucks with his head. Nowadays, Sam’s best distinguished by his resolute self-control: the discipline that keeps him working out and eating right and so constantly, carefully chaste. He knows, of course, that’s probably just the point, Sam’s unshakable restraint the necessary counter against his still-pulsing, dirty desire. But nevertheless, it’s hard to square his increasingly ascetic brother with the headstrong, power-hungry kid who once tumbled so desperate and reckless into Ruby’s clutches.

He wonders what it tastes like, demon blood. Like sulphur, he supposes; like death. But maybe he’s wrong. Maybe the stuff is intoxicating, heady like perfume, ether chemical-sweet. In the past, he has sometimes thought that it might taste like the smell of Sam’s skin: a subtle, woodsy, rosemary scent that clings to his brother’s clothing and that has, on occasion and in Sam’s absence, brought him to tears. (Turning up a worn T-shirt from the bottom of his duffel when he was running the first load of laundry after Sam left for college; burying his face in Sam’s stupid, ugly shirts, hunched over the back of the tarpaulined Impala in Lisa’s garage.) It’s a stupid thought and one that, now, seems strangely distant; he can access it but it’s like looking through the wrong end of a telescope, his feelings all withered down to a tenth of their normal size. Demon blood, human blood... Sam's right, there's no difference, not really. Dean found out when he was a demon himself that the Mark can be satiated with it either way.

Thinking of satiation, watching Sam swallow, Dean’s struck by a thought.

“Don’t drink it all,” he says.

Sam flinches. “I never asked you to watch this.”

“No. I mean. For after. Don’t you think it might be better to, you know, come down slowly? Last time – both the last times. It was brutal, man.”

“I’m not drinking it after,” Sam says, tersely, fiercely. “I just want to get it out of my system as fast as I can. I’m fucking fed up of all this crap inside of me, clogging me up.”

~~~

There’s a circle on the ground, a wide one, etched out on the concrete in chalk and hedged around with symbols that send a shiver over Dean’s skin when he crosses them. Sam has set a chair in the circle, a bent old plastic thing that might once have lived in a schoolroom, and Dean wonders for a moment why the seat is so off-centre, close up towards the circle’s near edge. Then Cas appears with a wrapped-up bundle that sets the Mark singing, ripples of power running down Dean’s arm.

The First Blade. Cas takes it out, sets it carefully on the ground at the far side of the ring. Dean wants to get up, cross the distance. It’s just a few paces away. And his hand is aching for it, a sharp splintering pain running right through the bones of his forearm. It doesn’t seem so unreasonable, just to hold the thing one last time.

Cas stands on the edge of the circle, just outside it, just beyond the Blade. Dean looks longingly at the stubby curve of bone, the teeth uneven in the sockets; he seems to feel the smooth warm grip of it under his palm. But Cas is there, his feet in their stupid sensible shoes framing Dean’s vision; and Dean knows that when he looks up Cas will be frowning disapproval. So he doesn’t; doesn’t look up, but doesn’t move either, just sits where he’s been put.

Sam’s standing behind Castiel, some yards away, with his back to Dean. He’s bent over a trestle table that they’ve set up as a makeshift altar; ingredients lined up in a neat row along the far side of the bench, the book Dean found in the bunker’s archives splayed open beside him with Ruby’s knife weighting it down. Dean killed Ruby with that knife, with the blade she gave them. He sank it deep into the the bitch’s belly and he watched her eyes flicker fire as she faded away. It’s a nice feeling. A good feeling. He did that for Sam.

That’s the thing, though, isn’t it? He did it for Sam, but he was too late to fix the real mistake. Killing Ruby felt good, felt fucking fantastic, but it didn’t stop Lucifer rising and it didn’t save the thousands of people who died in that apocalyptic year. It didn’t save Ellen. It didn’t save Jo.

Dean looks towards Sam, bent oblivious over the copper bowl in which he’s casting the spell, and he feels a calm sense of certainty settle over him. This isn’t the way. Dean trusts Sam, and he trusts Cas - he does. He trusts them to mean well, and to try to do the right thing. But he doesn’t trust them to know _best_ , to think clearly, to see what’s really right, not where Dean’s own well-being is concerned. It’s all - it’s so fucking obvious. This has to be a trap.

It’s a trap, and Sam’s fallen into it, but Dean can pull him out.

 _Yes,_ Dean thinks. He reaches out his hand, arm straight, fingers splayed; and the Blade flies straight into it, lifting swift as a slingshot away from the ground beside Castiel’s feet. As soon as the handle hits his palm, Dean’s electric all over, thrumming with power. He crosses the circle in five bounding strides, takes two more and then he’s at Sam’s back with the blade in his fist and the blunted point of it between Sam’s shoulderblades. Sam hasn’t even turned round; too absorbed in his magic, or perhaps it’s just that Dean’s moving faster than the world around him, suffused as he is with light. It’s better this way. Sam won’t know what’s hit him; what’s saved him. Dean lifts the weapon, ready to strike.

Dean has the Blade high over his head, clenched tight in his joined fists, when Sam tells him to stop. He’s not speaking English. The word is guttural, low. But it shivers through Dean’s system like ice.

Sam turns around, pushing forward, and Dean steps back. Sam’s face is flushed, a hectic line of colour over his cheek, and his eyes are dark, the irids huge, expanding into black. _Get back_ , Sam hisses, or that’s how it feels, and Dean tries to fight against it, tries to find the strength that he was glowing with just moments before. It’s fruitless. Dean feels Sam’s power holding him back: feels the twist of his mind tugging deep inside Dean’s gut and ripping at him from the inside. Dean coughs a little, black smoke. This is him, disappearing, his own essence wrenched out of him and then that’s it, he’ll be straight back to hell amidst the bones and the fire, back on the rack or slapping other people onto it, slicing open his own being with every pass of the blade. He’s thrashing and furious, foaming with impotent rage; but Sam has him pinned, advancing with his hand outstretched and his teeth bared and a dark, fixed purpose in his eyes. Dean howls and Sam glances momentarily away, back over Dean’s shoulder where Cas must be waiting, before he brings up his other hand and starts speaking the spell.

Though he’s got the basics of Enochian pronounciation, Dean still doesn’t understand the language: he didn’t have Sam’s long apprenticeship in the Cage. But these words touch him with something visceral. All the anger that has been brewing for the past year boils inside him, bubbles, multiplies, dividing and dividing into black cells of fury so that every bit of him is made up of driving rage. The Mark burns on his arm like a brand.

Sam is standing quite still in front of him now, lips still moving, eyes never leaving Dean’s face. The spell continues and the Mark is wailing and Dean opens his own mouth and screeches his fury, everything he’s ever thought or envied or hated about Sam, all the tiniest resentments and the longest-held grudges, everything he knows that is best calculated to hurt. Monster, he calls him; filthy devil-fucker, mother-killer. He screams at Sam for all the times Sam let him down, strings him out for all the things Sam ever did trying to save him. I hate you, Dean tells him. You’ve ruined everything, ruined me. You’re disgusting. You are obscene.

He’s crazy with anger, thrashing against Sam’s implacable power, feeling his muscles strain and tear and the rawness at his throat spit blood and then suddenly, suddenly, Sam stops speaking and a jet of blue light arcs from his right hand across the concrete and into Dean’s arm. Dean looks down. The Mark burns for a moment hotter than ever, dazzling white, jerking tears from his eyes; and then, so quietly, it flares out and shimmers away.

Sam’s power over him retracts, a hand under the shoulder suddenly dropped, and Dean stumbles forward, almost falling. He catches himself and stands for a moment, breathing, holding his naked arm out in front of him; seeing and not trusting the unmarked skin. His breath is coming in painful heaves, his airway torn and corroded with screaming and bile. He hurts all over. It’s like somebody took a rolling pin to every muscle in his body. But the Mark is gone, and his mind is finally, blessedly clear.

Ahead of him, Sam makes a snuffly, stifled sound. Dean looks up just in time to see him drop; but it’s Castiel who runs forward to catch him, who wraps his arms firm around Sam’s middle and lowers him carefully to the ground. The pair of them settle into a configuration that Dean knows well from playing his part in it so many times. Sam is on the floor, legs sprawling. Cas is crouching beside; his hands on Sam’s shoulders, his face lowered to catch Sam’s eye.

Dean steps forward, unsure.

Sam’s face is a mess of blood and snot and tears. He gasps in short, hitching, desperate gulps of air; and Dean watches with a jerk of guilty jealousy as Cas lifts his hand to run it soothingly over Sam’s hair. But Sam looks up at Dean where Dean stands over him, and he nods, because he can hardly talk; he smears back the gunk all over his face and he smiles and he sniffles and he breaks Dean’s heart.

“You’re okay, Dean,” Sam tells him. “I’m okay. You’re okay.”

Dean watches as Sam reels himself in, forces the tears in and the cheer out until he’s shaking with the effort. Not fooled, Dean thinks about objecting: about telling his brother, “I see you. I know what you’re doing.” But in the end, it doesn’t seem fair. The lie is an important part of Sam’s forced composure, a building block and if Dean tugs it away he’ll have to deal with the full extent of the destruction that his choices have wrought.

Instead he nods, breathes out, watches Sam almost relax.

“This probably calls for a beer,” Dean says.


	4. Chapter 4

Piled into a motel room on the outskirts of town, the three of them get through a whole lot of alcohol in the course of the night: a cooler full of beers and a warm bottle of whisky that Cas produces triumphantly from an inner pocket of his coat. Despite this contribution, Cas probably doesn’t get drunk. But Dean does, a little; and Sam does, significantly: not as hardened as he might be by what Dean suspects have been several long, lonely nights of self-anaesthesia over the past two years.

Sam, when he’s happy, is a cuddly drunk: smacking his big hands into the sides of Dean’s face, leaning on him pliant and sloppy and smiley, gesturing with wide open arms. Even when he’s worried, or scared, drink tends to relax him: to set long-guarded secrets and innermost feelings spilling recklessly free. It’s a weakness that Dean’s often found occasion to exploit. Tonight, though, at least to begin with, he’s only half-successful. Several times, he catches Sam sneaking what he probably thinks are subtle glances at Dean’s naked arm. More than once, he sees Sam extending careful fingers towards him, snatching back his hand like burning as soon as Dean shifts. But whatever Dean does, however close he leans and however much he smiles and however unthreatening he tries to make himself, Sam just can’t seem to work up the courage finally to bridge that gap.

Eventually, it gets to the point where Dean’s drunk away enough of his shame just to offer his brother his forearm. Sam looks at him, nervous. Dean shoves the limb into his face.

“For God’s sake. Go for it, Sammy,” he says.

He thinks for one awful moment that Sam isn’t going to do it: that maybe, Sam won’t ever touch him again. But, finally, Sam reaches towards him. Pat pat, he goes, fingers floppy over Dean’s skin. Pat pat, over the space where the Mark deformed him.

Pat. With his hand still heavy on Dean’s arm, Sam looks up into his face and smiles a sunbeam of a smile, unleashing his dimples and leaving Dean blinking, dazzled by light.

“It’s gone,” he says.

“Yep, it’s gone,” Dean agrees.

He’s glad to feel Sam’s fingers warm and sweaty against him; but there’s a little black knot in his stomach that won’t dissolve. It isn’t just the Mark that’s disappeared. All the years of their childhood, of their adolescence, of their stupid youth, there used to be something binding Dean to his brother: something unbreakable, the strong spinal cord of his life. Now though, that tether is twisted, maybe snapped altogether. It’s enough to leave Dean paralysed.

The emotion’s redundancy makes it doubly embarrassing. It’s not like it’s a new thing, this distance between them. But Dean seems to be feeling it freshly: a consequence, perhaps, of the rush of emotion back into his system after the lifting of the Mark. It’s like the new skin that grows over a wound. His feelings are sensitive, pink. More than maybe any time since Sam got back from Hell, Dean _misses_ his brother. That was the cruelty of… of RoboSam, the other guy, whatever you want to call him. Dean was missing Sam and Sam was still right there. He wonders if that’s what Sam’s felt about him, these past several months. These years.

“Dean,” says Sam, breaking into his reverie, comically serious.

“Yep,” Dean says, reaching for a grin.

“I was thinking,” says Sam; and suddenly Sam’s face is looming, Sam right beside him, his breath sour and alcoholic and warm against Dean’s skin. Dean doesn’t move. He’s scared, suffused with an adrenaline that feels dangerously akin to the held-back power of the Mark. Dean doesn’t move but Sam does, his face inching closer and closer until his mouth is colliding with Dean’s in what is definitely a kiss.

It doesn’t go anywhere. Dean doesn’t move, or open his mouth. He feels frozen, honestly, pinned into place by the butterfly pressure of Sam’s lips on his. It’s only a moment; a few seconds, just a little too long to be explained away. And when Sam draws back, he doesn’t catch Dean’s eye. What he does is almost more confusing: he looks at Dean’s mouth, a slow, unfocused stare that might only be drunkenness, might be lust.

Dean doesn’t know what to say. It’s only for the past few hours that he’s really felt anything. His emotions aren’t prepared to deal with something this precious, this big.

So he says nothing, does nothing, stays just where he is and freaks out internally and waits to see what Sam does next.

“I’m glad you’re back,” Sam says. He sways backward, smiles at Dean again, the same big goofy grin as before.

There was once a time when Dean could read every single little thing Sam did.

“Okay,” Dean says, “yeah. Me too.”

“And I’m certainly glad,” says Cas; and that’s it, that’s enough to shift the atmosphere back into something like what it was before. Sam reaches over for another beer; Dean slaps his hand because the kid’s had quite enough; Cas solemnly downs another finger of whiskey; and the night carries on unravelling toward the dawn.  

~~~

In the morning, Cas wants to know if he should go: “You might need some space,” he says, inconveniently perceptive. Nervous about being alone with his brother, Dean is about to suggest that the angel stay; when he realises that it isn’t him who Cas is asking. It probably doesn’t say very nice things about his character that even this small gesture of respect for Sam’s wishes pricks him into annoyance. Who is Cas to care about Sam, when in the past he’s helped to betray him in so many ways?

Sam, less troubled (more forgiving), considers Cas’s offer; tells him eventually, “Yes, thank you;” and crushes the angel in a bonebreaking hug that makes Dean ache with longing right down to his marrow.

“I couldn’t have done it without you,” Sam says, choked, into Cas’s shoulder. Dean digs his toe into the gravel at the side of the road.

It takes Dean a little while to shake the bad mood; but if anything can bring him joy it’s flying along in the car, the Impala’s engine roaring strong underneath him and the trees blurring fast through the windows outside. It’s a beautiful April day. The sky is blue and the air is fresh and Dean finds himself almost dizzy with it, giddy with relief, tingling all over with the glorious sensation of finding happiness in something so small. He feels good right through, quick and nimble and mercifully free of the stifling weight that’s hung on him since he first grasped Cain’s hand. It’s like everything’s more real, more vivid: like the world’s shifted back into Technicolour after months of wearying black and white.

This is especially true of Sam. Dean keeps looking over at his brother. Little bits of Sam’s face jump out at him: his moles; his eyebrows; the tilted slope of his nose. Dean likes all of them. This is how it feels.

“Hey, Sam,” he wants to say. “I don’t want to kill you. Not even a little bit. Isn’t that great?”

He _doesn’t_ say it, but the thought remains, reassuring, at the back of his mind; even as the road spools on and his mind rushes forward with it, accelerating on down the tarmac to their eventual destination. Dean’s stomach sinks a little at the thought of the bunker; at the thought of slotting back into the narrow walls of the maze through which he’s been stalking his brother for the past twelve months. He imagines walking past the patched-up wall where his hammer missed Sam’s head, without the insulating cushion of disinterest that the Mark provided.

He looks across to the passenger seat. Sam’s gazing out through the windshield, unfocused, his expression mercifully clear.

"Wanna take a diversion?" Dean says.

Sam looks at him, surprised, but not unwelcoming. "What did you have in mind?"

~~~

It's only spring and it shouldn't be so warm in New York but it's like the whole world is sharing in Dean’s good mood. The sun is shining brightly and the car heats up quick.

Dean drives steadily and with purpose for the next three hours, until at last he pulls up at a spot where the road widens, deep in the woods. Sam looks quizzical, but Dean just grins at him and gestures into the trees.

A short stumble through the forest brings them out onto a wide expanse of water. The lake is quiet and dark under the bright, still sun, and the forest is thick and green all around. In front of them, the rocks climb over the edge of the water, extending low and wide like a jetty.

“We’ve been here before,” Sam says. It’s true. Dean hasn’t been driving back and forth across the continental US for the whole of his life without generating a mental list of his greatest hits. He’s come here for a reason, with a memory in mind. But he doesn’t say that, just grunts in agreement and walks on down towards the shore.

They set up a kind of picnic at the side of the lake, spread out on one of the broad, flat rocks, digging into the sandwiches and soft drinks and chips that they picked up at a gas station forty minutes back. When they’ve eaten, Sam lies on his back in the sun, his closed eyelids fluttering paper delicate and his eyelashes fanning dark across his cheek.

For a long few moments, Dean savours the sight; Sam, catlike, catching rays. The thin stubble on his brother’s jawline glitters golden in the light; and Dean traces his eyes over the lines of Sam’s face, the cut of the chin and the delicate bones and the shadowy hollow of Sam’s cheek. Then he pulls himself together.

"Come on, Sammy," Dean says. "Last one in the water pays for dinner tonight."

Sam groans; but he clambers upright and bends to shuck off his shirt, shedding his clothes methodically into a tidy pile of denim and plaid. Dean, still sneaking glances at his brother, is shocked. Sam's body, which has been nut-brown and chiselled since the summer half a lifetime ago when he shot up six inches and turned seventeen, is slimmer and paler than Dean ever remembers seeing it; freshly marred by a long white scar that twists over his right shoulder. This must be the injury that had Sam in a sling last summer. It’s not quite the simple dislocation that Sam had implied.

There's another alien element to his brother's torso in the shiny pink burn that discolours his chest, just at the spot where Dean’s own body is marked by his tattoo. There's no sign that Sam has done anything to replace his own protection since the moment over a year ago when Cas burned it off him at Dean’s request.

Both scars combined prompt a quick flash of anger. Fuck’s sake, Dean thinks. Sam. Take care of yourself.

He doesn’t say it: he’s still stuck on his best behaviour, trying to make up for what went down over the past eighteen months. Instead, he tugs his own pants off quickly, shrugs out of his T-shirt and dive-bombs into the lake, splashing icy water back over Sam where he’s still getting changed.

“Unlucky,” says Dean, but Sam just shakes his head.

“You realise we share finances, Dean,” he says; and slides graceful and naked down off the rock. Ducking his head straight under, he comes up dripping and launches in a confident breaststroke out across into the deeps.

Dean doesn’t follow. Instead, he lets his legs drift up to the surface; lies there with the cold chill of the lake cradling the back of his head, feeling the sun over his cheeks and on his nose. He lets his thoughts empty away, consciously pushing out everything beside the moment’s immediate physical sensation. It’s been a long time, such a long time, since he’s felt so calm.

The trees around the edge of the lake have an insulating effect, so that none of the sound from the road filters through. All Dean hears is the lapping of the water against the rocks, the soft splash of a surfacing fish, the chirping song of the birds. Out at the edge of his consciousness, there are the rhythmic sounds of Sam’s swimming. It lulls him. The thing about the Mark was that it cut him off: from everything, from himself. Out here in the water, under the sun, he can feel the connections re-forming, links curling out like tendrils, binding him into the world.

Dean’s been floating for a good while, clear and peaceful, when suddenly there’s a hand on his shoulder and he’s plunged deep and sudden down into the chill. Choking and gasping, he claws his way back to the surface to find Sam laughing, treading water right beside him.

“Dude,” Sam says, “Were you actually asleep?”

Dean can’t talk for a moment, still catching his breath; but there’s nothing wrong with his eyesight, and there’s a blue tinge to Sam’s lips which doesn’t look healthy. Too long in the cold, Dean decides; and when he’s finally able to function properly, he kicks off back towards the rocks where they slid in.

Sam follows him and they sit there together, basking, drying in the sun. It’s a long time before either one of them says anything, but eventually Sam breaks the silence.

“How does it feel? Not having the Mark.”

Dean considers it, tries to find the words. “Lighter,” he settles on, eventually. “Like I can think for myself.”

Sam nods.

“I can feel things better,” Dean says. “It might… I don’t know. Do you remember how it felt, getting back your soul?”

Sam walks his two fingers down a deep scratch in the rock. “Not really,” he says, looking down at his hands. “It wasn’t straightforward. You know. To start off I didn’t even remember it had happened. I couldn’t remember, or wasn’t supposed to. And when I did, it was almost… it was kinda like watching a movie, inside my head. I could see him do stuff but I couldn’t really figure out why.”

“Yes,” Dean says.

“And when I got all of it back,” Sam says, “I got Hell, too. So that fucked me up of itself.” He looks sideways at Dean. “And then Cas took that. Which, don’t get me wrong, I’m glad for. But now that’s another set of memories that aren’t properly connected. Or something. I don’t know.” He runs a hand through his hair. “It’s a bit… I don’t know. I can feel a bit funny, in here.”

“In here?”

“In my own skin,” Sam says. “It feels like, I don’t know. Like all of our houses. Like I’m not quite sure I’m at home.” His gaze flickers, nervous. “Sorry. I know you don’t like when I say that.”

“It’s fine,” Dean says, heavily. “Fuck, man. I can hardly blame you if you feel uncomfortable there, not after… you know.”

“Yeah,” Sam says. “You can’t… you didn’t mean to, man. It’s okay.”

It’s not okay, but Dean doesn’t bother to dispute the point; and the pair of them sit for a little while longer, silent, gazing out at the trees across the lake.

Eventually, Sam shifts. He clears his throat.

“Did you. Um,” he says.

“Did I what?”

"No, sorry, it's weird."

Dean watches the water. "I'm not going to shout at you, Sam.”

“I know,” Sam says.

Dean waits.

“Did you ever, you know. Smoke out. When you were a demon. Did you ever possess someone?” Sam says.

Dean hears the waver in his brother's voice. He feels the weight of the question, suspended between them.

“No,” he says. “I didn't, Sammy. Never, okay? Not once.” Christ in heaven but he's grateful for the casual, careless chance that's let him answer this honestly without losing Sam forever.

“Okay,” Sam says. He picks a pebble out of the crack in the rock, poises it on the flat plane of the surface, and flicks it out over the water. It lands with a tiny splash, and disappears.

~~~

They stay out on by the lake until the sky turns pink and Sam starts to shiver: and even then they just drive down the road to the diner in the next small town. Dean orders steak and potatoes for both of them and tries to slip bits of his food onto Sam's plate. Sam forks doggedly at pieces of greenery, carrying them to his open mouth with fingers that are still trembling, and Dean worries about the chill in his brother's bones.

When they get back to the car, he goes rooting around in the trunk, searching his duffel for the soft grey hoodie that he likes to wear to work out. Successful, he drops it through the window and onto Sam’s lap.

“Put a sweater on, Sammy,” he says. “And close the window while you’re at it. It’s freezing out here.”

Sam, still shivering, shakes his head. “No thank you. I’m too hot,” he says.

God knows Sam’s always been stubborn, but it’s weird for him to be so defensive over something so small. Still, Dean reflects, Sam’s had good reason lately to be cautious about exposing his weaknesses. So he lets it slide. That’s the new policy, right? Don’t boss Sam around, don’t tell him what to do, don’t remind him how you told him you were running a dictatorship before you gracelessly punched him out cold. Still, Dean leans over to the Impala’s heating control and ratchets it round a few notches, setting stale warm air wheezing out of the vents.

Sam huddles in the passenger seat while Dean drives them back to the lake, passing the spot where they’d stopped off earlier to drive around to its far side where a cabin sits dusty under the trees. He hauls the sleeping bags out of the trunk, carrying both of them into the house with his duffel slung over his back. Ahead of him, Sam stumbles under the weight of his single bag, weaving almost drunkenly up the dirt path to the door. Kid must be dead on his feet. He sleeps badly at the best of times and Dean can’t imagine that it could have been easy lately for Sam to get much rest, locked in an underground chamber with a brother only half-himself.

Inside the cabin, little has changed since the summer fifteen years ago when they stayed here last. It was dilapidated then: now it’s almost derelict, a thick layer of dust over everything that makes Sam sneeze when Dean scrubs at it with his discarded overshirt. It’ll have to do. But Dean makes sure that Sam gets the good roll-mat and most of the extra comforter he digs out of the back of the car.

Lying close up beside his brother on the floor of the cabin’s main room, half-dozing and half anxiously monitoring Sam’s uneven breaths, Dean drifts back to the last time they were here, a few hot weeks in August 2001. Sam and John had been fighting every moment back then, Dean stiff with the tension and sore with the effort of trying to keep the peace. Then, in the last week of July, John’d got a call from somebody, Bobby or Travis or Jim, and set off hell for leather into the distance, leaving the pair of them cooped up here with nothing to do. Well. Nothing but each other.

Maybe half of the reason that Dean hates Ruby so much, that he still hates her so much he’d like to kill her all over again, is that he blames her for putting an end to what he had with Sam. So yeah. Dean had come back from Hell angry and fucked-up and not really in a state to be getting in bed with anybody, probably least of all someone he loved. But it was Ruby (wasn’t it?) who kept prying them further apart; and it was the stomach-burning, furious jealousy she provoked that stopped Dean forgiving Sam the betrayal until it was really too late, until Sam was a night away from jumping into the pit and they spent those last, desperate hours together on Bobby’s sagging spare bed. And after that… well, after that it was Lisa and then Sam-who-wasn’t-Sam, and Sam restored but fragile like an oyster out of its shell, and the year Dean spent pickled and desperate and half-ready to die, and then Purgatory and the long, slow, bitter split of the last few years.

It’s an absence. It’s an absence, Sam there but not _there_ , and lying here in the cabin with his brother so near him, Dean’s consumed by the need to close the gap.

He shuffles up behind Sam, sleeping bag hissing across the floorboards, and spoons himself tight along his brother’s back. As Dean makes contact, Sam’s muscles tense. For a moment, he doesn’t move; just freezes, rigid, barely breathing. Dean’s face is almost in Sam’s hair. He can smell it, can feel it brushing soft over the tip of his nose. But after a moment, Sam wriggles, shifts away - just a little - and turns around so that he’s facing Dean. His face is pale in the darkness of the cabin, his eyes registering as great black holes in the skin of his face.

Sam angles his big black-hole eyes toward Dean. “You okay?” he says. He’s whispering, although there’s nobody to hear them.

“Yeah,” says Dean, “yeah,” almost under his breath. Then he says, “I don’t know;” and, _“Sam;_ ” and he leans forward a little more, just closing the gap, presses his mouth against his brother’s for the second time in twenty-four hours.

For half a second, it seems like Sam is going to respond. All the tension drains out of him, and he opens up, his lips soft under Dean’s.

Then Dean reaches out, settles a hand on Sam’s waist or hip; and his brother shoots backward, scooting back across the floor, a great ripping sound tearing into the air as the shiny outer fabric of his sleeping bag catches a nail. The noise is enough to shatter the atmosphere. It might have done it, even if it hadn’t happened only because Sam couldn’t get away from Dean fast enough. As it is, it’s cold water chillier than the shock of the lake.

“Sorry,” says Dean, dazed.

“No,” Sam says, scrambling into a sitting position. The lining of his sleeping bag, split like the belly of a fish, bulges outward from his shins.  “I’m sorry. It’s my fault. I shouldn’t have… I shouldn’t have, last night.”

“It’s fine,” Dean says.

“I just.” says Sam. “It’s just… it’s too much. Right now.”

“Don’t worry about it.”

“I’m not saying never,” Sam says.

Dean should appreciate that; should savour it. It’s more than he would have hoped. But right now he’s still stinging with embarrassment, too absorbed in the sensation of his rightly wounded pride to process what he might come to appreciate more in time. “Look,” he says, loud in the darkness, “it’s okay. You don’t owe me anything, Sammy, and I owe you a fuck of a lot. Okay? I crossed a line, fair enough. Let’s go back to sleep.”

Sam’s silent, and he doesn’t move until Dean repeats his name, sharper; but then he nods his head, and shuffles obediently back to his place on the mat. Dean backs off, slides away until he’s where he started, watching the rise and fall of Sam’s shoulders in the dark.

“I’m not saying never,” Sam says again, quietly, but Dean doesn’t respond. Fuck sake. How much is it fair for him to expect Sam to give?

~~~

Sam’s still shivering when they wake up, pale and peaky looking enough that Dean’s awkwardness about the night before is quickly subsumed in concern. He drives them back to the same diner where they ate last night, orders Sam a short-stack of pancakes with bacon, and watches hawk-eyed as Sam fails to eat any of it, crumbling the batter and pushing it around the plate like it might disappear of itself.

“You gotta eat,” Dean says, before he remembers that he isn’t telling Sam what to do. “Or not,” he says hastily, cutting off the apology that’s already forming on Sam’s lips. “Whatever. Up to you.”

Sam looks suspicious but he doesn’t complain, slides the plate across the table. Dean digs in.

“So,” he says, around a mouthful clogged with maple syrup, “where next?”

Sam looks sideways, out of the window to where the Impala is sitting shining in the sun. He drums his fingers on the table. “Home?”

“Home?”

“Back to the bunker, then,” Sam says.

Dean would be lying if he said he wasn’t disappointed. He’d hoped for a bit more we-time; for a few more days on the road. The bunker’s not an appealing prospect, stuffed as it is with bad memories. But this is Sam’s time, up to Sam, what Sam wants Sam gets. (Dean can’t help thinking, also, of the cabin last night. Maybe Sam wants the safety of his own bed, of a lockable door.)

“Sure thing, Sammy,” he says; and when he peels out of the parking lot, he turns the Impala south.

~~~

They’re maybe a third of the way back to Lebanon when things get real. Sam’s been dozing in the passenger seat, head knocking soft against the glass of the window, mouth hanging half-open in a way that should look dumb but which is actually inexpressibly endearing. Okay, Sam’s taken some hits. He’s tired, worn out, kinda pale and thin. But in the time that it takes for the guy on the radio to change the song, Sam drops like a stone, all the way from ‘could look better’ to ‘Death’s fucking door’.

Dean misses the actual moment of transformation; he’s watching the road. But he hears Sam gasp; and when he casts a hurried glance across the car, Sam’s shaking; like really shaking, not the tremor that has dogged him since yesterday, but a big movement that rattles his whole skeleton, scary and out of control.

Dean looks at the odometer like it's gonna somehow recalculate, like they're gonna be two hours out from Lebanon instead of fifteen. Then he looks back at Sam, blotchy-faced and sweating. He's jiggling his leg, clenching his hands into the fabric covering his thighs. He breathes, deep and raspy, like it needs concentration.

Fucking Christ. Dean didn’t… in the euphoria of getting free, Dean didn’t even stop to consider that this was coming. He plain forgot.

Well, it’s coming now and they’re in the middle of nowhere.

“Sammy?” says Dean.

Sam looks at him, kinda. He’s blinking rapidly, his forehead bunched, confused. “Sorry, sorry Dean,” he says. “Sorry. I’m fine. We can keep going.”

Dean tries. What Sammy wants, he gets, remember? But now Sam’s mumbling in the passenger seat, “it’s okay, Dean, it’s okay,” when actually it’s pretty fucking obvious that things are anything but. Dean nudges the brakes. “It’s okay,” Sam says again. “I can do this. You don’t have to…”

"Fuck this," Dean says. Outside, a flaking sign lets him know that the Lucky Strike Motel is just three miles up ahead. "AIR CONDITIONING," it says. "CABLE TV IN EVERY ROOM."

Great. At least Dean will have something to watch while Sam writhes in agony on the twin bed beside him.


	5. Chapter 5

Dean swings the Impala round into the forecourt of the motel, a long low single-storey building painted with slot machine motifs. The woman behind the desk raises an eyebrow when Dean asks for the room on the far end, but shrugs her shoulders and slides him the key, never removing the cigarette that hangs from her lips. Her nails are painted a bright, shocking shade of mauve that reminds Dean suddenly of the bruise on Sam’s cheek, the colour it had been when he stepped into the library and saw Sam spread there under Castiel’s hands.

When he gets back to the car, Sam’s curled over in the front seat, clutching his knees. His hair is already damp with sweat and when Dean puts a hand on his back, he flinches.

“Sorry, Sammy,” says Dean. “I need to get you into the room, OK?”

Sam nods, but his hands don’t leave his knees and Dean has to lean over to pry the fingers open and off. He offers his own hand to Sam then, pulls him up, steadies him as he sways unsteady on the asphalt and props him up against the car as Dean grabs all their shit from the trunk. Once he’s got the bags slung over his shoulders, he takes Sam by the elbow and steers him along to their room. Thank God for this place being in the middle of nowhere. There’s no sign of movement from any of the other rooms and Dean’s hoping, hoping they won’t be disturbed. The other couple of times they’ve done this, Sam got kinda loud.

“OK.” The door swings open on a dispiriting twin-bedded room, grey-green wallpaper with an indistinguishable swirly pattern and garish red-orange linens on the beds. There are two windows, but they’re not large and even in the afternoon light the room is pretty dark. Dean leads Sam to the nearest bed, sits him down on the edge of it, steps back to assess. The colour of Sam’s face concerns him. Sam’s white where he’s not flushed a hectic pink, bright spots on his cheeks and dark circles already forming under his eyes. While Dean is watching, Sam lifts a trembling hand, pinches hard at the bridge of his nose. A headache, then.

Dean inwardly curses himself. He’s an idiot for not having thought this through.

“Hey, Sam,” he says.

Sam looks up at him, just for a moment – then his gaze skitters away, until he’s staring off into the distance somewhere beyond the bathroom door.

“Sorry,” he says. “Sorry. I was hoping we’d be able to get back home before this began.”

“You don’t gotta apologise, Sam,” Dean says.

Sam smiles, brief and painful. He wrings his hands tight in his lap. “Maybe it’s the shock of all of it at once, out of nowhere. It took longer before.”

“Well,” Dean says, useless. “We just gotta deal with it, I suppose. We’re here now.”

“Yes,” Sam says.

“About that…” Dean looks towards the window. “We might be stuck in this place for a while. If I’m gonna go get supplies, I better do it sooner rather than later. Right?”

Sam nods, but there’s an absence to the movement. Dean’s not sure how much he’s hearing.

“I won’t be long,” Dean tells him, backing hurriedly out of the door.

The nearest decent-sized store proves to be around thirty miles away, so it’s the best part of an hour before he returns, heart pounding an urgent rhythm in his chest. It’s crazy. Last time this happened he locked Sam in a metal room and pretty much sat on the key, so why he's now so desperate to get back to it he can’t quite say. Still, he feels a warm wave of relief when the motel’s battered sign finally makes its appearance between the trees at the side of the road; and he almost fumbles the keys in his hurry to close up the car and get back to their room.

He unlocks the door to find the room dark and oppressive, curtains drawn and windows closed and the air already turning stale. Sam is lying on the bed in the far corner of the room, curled up in a fetal position on top of the blankets. He is still wearing his shoes.

Dean approaches cautiously, hoping Sam’s asleep. But as he steps closer, Sam lifts his head. He makes a soft, indistinct noise.

Dean gestures with the bags he’s still holding. “Got some stuff,” he says. “Food. Painkillers. Gatorade.”

Sam nods, drops his head back down; and Dean hovers for a moment, uncertain, before he turns to unpack. He’s trying to be quiet, which of course means that every plastic packet or paper bag rattles like goddamn gunfire.

Once he finally gets everything out, Dean feels a sense of relief that’s almost comically fleeting. Now what? At a loss, he lines up everything neatly, all the groceries in two smart rows. It takes about thirty seconds. Okay. Well. He’ll just stand there quietly and think about his next move.

“You can put the television on,” Sam says. He’s still facing the other way.

“Your head’s hurting,” says Dean.

With an effort, Sam hoists himself up, shifts around so he’s leaning on one elbow and looking at Dean. His colour is terrible; his hair is sticking to his face.

“It’s not… it’s gonna be a long time before things get dramatic,” he says. “I’m just gonna be low-level miserable for the next twelve hours.”

Dean is quiet.

“Seriously,” says Sam. “If you want to get another room, it’s okay. Then you can watch TV, or whatever, without worrying about my head.”

“Oh come on,” Dean says. “I’m not leaving you here on your own.”

Sam opens his mouth, closes it. He takes a deep breath. Then he twists back over, flops down on his stomach onto the bed. He says, to the wall, “I’m not going to leave.”

“Huh?”

“It’s not… you don’t have to keep an eye on me. Lock me down. Whatever. I don’t… It’s not like the first time. I’m not going to go out and look for more of it. I’m not trying to save the world.” Silence. Then, “Fuck,” says Sam wearily. “I don’t even care. Chain me to the bed if it will make you less worried about it. It’s hardly going to make me feel worse.”

Hell if that doesn’t make Dean feel like shoe-shined shit. But he chokes down his anger and apology both, and rattles the aspirin in its plastic bottle. “No chains, no TV,” he says. “Now take some painkillers. And try to sleep.”

Sam swallows the tablets obediently, hoisting himself awkwardly up on his elbow to do so, sipping at the bottle of water Dean holds to his lips. He might say it’s not kicked in yet but he’s already half-helpless, letting Dean baby him like he’d never normally allow.

“Okay,” says Dean, and he bends over to pull off Sam’s boots. He tucks Sam under the scratchy motel blanket, settles an understuffed pillow under Sam’s head, and retreats to his own bed. Digging around in his bag, he comes up with an old, battered copy of _The Fellowship of the Ring_. “I’ll just be right here,” he says.

“Me too,” says Sam, and they settle into silence.

Dean can tell that Sam’s not really sleeping: his breathing’s too careful, not quite regular. But somewhere in between Rivendell and Lothlorien, Dean himself dozes off.

He shakes awake some hours later to the sound of Sam vomiting into the carpet. He’s on his hands and knees, on the small patch of floor between the beds and the bathroom door. When Dean sits up, Sam swings around, face guilty and flushed.

“I’m sorry,” he says. “I didn’t –” he gestures with his hand, towards the bathroom; but the movement cuts short as he folds back over, coughing out bile.

“Hey,” says Dean, “hey, hey, hey,” and scrambles uncoordinated off the bed (his limbs still stiff with sleep) to kneel beside his brother. He rubs a careful hand over Sam’s upper back, a slow tick-tock between bony shoulders that used to be solid. “You done?” he says.

“Maybe,” says Sam. “I hope so. I don’t even…” and he coughs again, but his stomach must be empty because he’s just retching nothing, choking painfully on the air.

“Okay,” says Dean, soothing, and he tugs at Sam’s shoulder, settles his brother in a sitting position with his legs out straight in front of him and his back against the end of the bed. “I’m gonna get you some water. Stay here.”

Sam drinks the water, but he can’t hold it down for more than a few minutes. As he throws up into the trashcan, Dean holds back his hair and starts to think about the other times that Sam went through this. The Lucky Strike is hardly fucking Caesar’s Palace, he knows, but it’s a helluva a lot more comfortable than Bobby’s iron-lined panic room. And down there, Sam was doing this all alone.

Dean helped to clear the room out afterward, both times. He knows that shit got messy. It’s just different, seeing things up close.

Eventually, Sam stops being sick (or maybe it’s just that he stops really drinking the water that Dean’s trying to feed him); so Dean lifts him carefully, hands under Sam’s shoulders, and arranges him back on top of the uncomfortable bed.

“You okay?” he asks and Sam nods, twisting his face in painful imitation of a smile.

“It’ll pass.”

“Yeah,” says Dean.

Sam’s boiling up, stripped down to a T-shirt that’s stuck sweaty against his skin, so once he’s lying there quietly Dean ventures out to the motel forecourt to get some ice, stopping off at the dented vending machine for some drinks that are actually cold. As the bottles rattle down into the dispenser, he leans against the wall, presses his face into the concrete. The fresh air is a relief from the fetid, nauseating smell inside their room; the silence, the distance from Sam’s suffering a relief as well.

He picks up his drinks, the plastic chill and sterile and smooth, and he heads back toward the bedroom.

As he approaches the door, he hears an almighty crash. He throws it open just in time to see Sam fly through the air and go smack into the corner of the wall where the bathroom extends into the room. The sharp edge connects with the side of Sam’s head, a wince-inducing blow, but Dean at least is able to hurry forward in time to break Sam’s fall. Even thin as he is, Sam’s heavy, dead-weight like this, and they tumble to the floor together in an awkward slump. Dean dabs his fingers across the cut in Sam’s temple. It’s already swelling. It’s gonna bruise like a bitch.

That’s when Sam’s muscles go rigid. His head flings back and his mouth drops open and his arms lift stiffly before him. Horrified, Dean can only look on as Sam starts shaking with the tremors of a full-on seizure, gargling some ghastly sound at the back of his throat. It’s not like this hasn’t happened before. Dean should know better by now, should know how to deal with this, but everything he’s ever tried to read goes out of his head. He tries to make himself soft, leans away from Sam’s flailing fists and watches to make sure that Sam doesn’t slam into anything else that will bruise him. He thinks about Sam in the panic room, muscles straining against the leather belts binding him to Bobby’s rusty camp bed.

The seizure doesn’t last long, maybe thirty seconds; but Sam is effectively out of it for a long while after, groggy and disoriented and scared. Dean tries to lift him back onto his bed, but the last thing he wants is to drop Sam and hurt him, so in the end he settles for piling the comforters from both beds, along with their sleeping bags, onto the floor; making a kind of nest where Sam can lay down and where he’s in no danger of hurting himself if (God forbid) he starts seizing again.

Curled up among the blankets, Sam seems to sleep, and Dean finds himself exhausted. Climbing onto his bare mattress, he lies down with his head at the foot of the bed, close to his brother. He closes his eyes.

~~~

Dean’s looking at himself in a mirror, something that he’s done often enough before. His hair is longer than usual, soft not spiky, and his shirt is red. If he were to blink his eyes, he knows they’d shift sharply to black. But he doesn’t do that. Instead, he tips back his head, opens his mouth and unfurls in a great gush of smoke. He can feel it, his atoms expanding, shaking loose. It’s a strange sensation, loaded with a weird kind of urgency; he has to make a conscious effort to keep himself together, to stop himself diffusing into ever more vaporous mist.

Down on the floor below him, his body slumps, empty, dead-eyed. Dean doesn’t need it any more: it’s time to find some new meat.

He gathers himself together in roiling clouds, whizzes out and up as the ceiling opens and transforms into sky. It’s a big, empty space but by now he knows where he’s going, and the stars around him blur rapidly into the green-grey tiles of the bunker. He speeds along the corridor, coils into an air vent and into Sam’s room; where his brother is lying on the bed, feet hanging off the too-short frame. _Yes_ , Dean thinks. He focuses himself down to an arrow of darkness, shooting with the force of a tight-strung bow into Sam’s soft, open mouth. He takes possession of what’s inside.

Dean strings himself out over his brother’s skeleton, settles himself into muscles and organs and stretches to feel his power. Somewhere very quietly, far away (somewhere like a panic room, down in the dark of the earth), Sam raises his voice in protest. Dean isn’t having any of it; forcing Sam down and silent with dazzling, dizzying ease.

It’s kind of wonderful, being able to make Sam do whatever he chooses. It’s what Dean’s wanted for a long, long time. Lift your hand, Sammy. Lift your leg, Do as your brother tells you, Sammy. Don’t do that. Do this. Do this. It’s wonderful, also, being inside Sam’s body; being beautiful, powerful, strong. Dean can’t keep his hands off it, Sam’s hands, whichever. He wants to touch himself all over; does.

Then the scene blurs, and Dean’s standing in a crowd. They’re jeering, hostile, and without even looking, he shoots out a hand and grabs onto the neck of the guy beside him. The guy’s choking, coughing, but Sam’s hands are huge and relentless. The man’s eyes bulge, his skin shifting into purple. Dean squeezes harder.

At the back of his mind, Sam starts screaming. “Stop! I don’t want this, stop!”

The guy’s mouth is moving, opening and closing like a fish, and his struggling limbs are getting weaker. Dean squeezes on and Sam is still screaming, “ _please_ ,” as the man turns darker, indigo-violet, and his eyes roll back in his head.

Dean wakes up at the exact same second that the corpse hits the floor.

What a horrible nightmare. But the relief is short-lived, because although it’s the motel room around him, although there’s no body on the floor beside his bed, Sam is sitting up in his blankets underneath him and he’s crying out just as Dean heard him doing in a dream not a moment ago.

“I’m sorry,” Sam’s saying. “I’m sorry I’m sorry please stop.”

Dean grinds his knuckles into his own eyes, squeezing himself awake. Jesus. This thing is relentless.

His hand must be only an inch away from Sam’s shoulder when “Please, Dean,” Sam says.

Dean stops dead.

Sam’s still speaking, an incessant low murmur that rises occasionally into a sob. His eyes are open, glassy; it’s clear that he’s seeing something that is not there.

“Please get out,” Sam says.

Dean’s spine turns to ice.

“Please get out, take it out of me, please,” and the tears are streaming down Sam’s face, “I just gotta, I don’t even, please just let me die, I don’t want to hurt anybody. Please. Not any more. I can’t.”

“Okay,” says Dean, although he’s not sure that Sam can hear him; and then Sam looks down, Dean follows his gaze, away from his brother’s blank white face to where his hands are laid in his lap.

“Jesus, Sam!”

There are long scratches down the length of Sam’s inner arms, startling and angry and Sam’s still scrabbling, gouging away with his fingernails into his flesh. God only knows how long he’s been doing it, and Dean curses himself for sleeping. Bright rivulets of blood run down to Sam’s elbow and drip dark onto the bedspread. What a fucking mess.

“Please,” Sam is saying, still. “Please, I don’t want it. I don’t want it. Get out.”

Dean goes to the bathroom, soaks a pair of hand towels in warm water, steps back in. He rests his hand on Sam’s shoulder, and Sam looks up. His face is blurry with tears.

“It’s in me, Dean,” he says. “I can’t get clean.”

Dean’s throat closes, suddenly: he can’t speak. But he takes Sam’s wrist in his own right hand, drapes a towel over Sam’s arm and wraps it tight. The blood soaks immediately into the dampened fabric. Sam looks down, confused.

“The blood,” he says.

“It’s OK,” says Dean, finding his voice. He binds the other arm. Sam flinches, this time, at the touch. “I’m sorry, Sammy,” Dean says.

“I don’t want it,” Sam says again, quietly.

“I know,” says Dean. “I know.”

~~~

Sam’s seeing things for the next few hours, different things, saying stuff that makes Dean want to climb out of his skin. But the worst, the worst happens when Dean comes out of the bathroom with a washcloth and Sam cowers right up against the wall, away.

“I’m not gonna hurt you,” Dean says. God knows who Sam’s seeing. Lucifer, Azazel. Him.

“Don’t kill me,” Sam says. “Dean will be angry.”

Yes, Dean thinks. Dean would be angry. And sad. Does Sam know that he’d be sad?

Sam beckons to him, fast and secret. He cups his hand very carefully over the shell of Dean’s ear, and whispers to him in a soft tiny ghost of a voice.

“I think he wants to do it himself.” As soon as he’s said it he claps his hand hard over his mouth. His eyes go big. “Don’t tell Dean I said that,” he says.

“I don’t - he doesn’t want to kill you,” Dean says. _How could you, Sammy?_ he wants to say. But it’s been how many days since he held a knife between Sam’s shoulderblades? how many months since he swung that hammer with all the intention to kill? It’s not like those are the only times he wished Sam dead. When he got his brother’s soul back, he’d had nightmares for weeks, thinking about how close he came to butchering the shell that was still half-Sam.

“Don’t worry,” Sam tells him. “I know it’s confusing. But there are definitely rules.”

Dean swallows.

“Let’s just try to be good,” Sam says.

Okay. No. Dean can’t do this any more.

He’s probably crying when he runs out to the car; probably crying or else his eyes are melting down, burning up like he deserves to for what Sam’s been saying.

He makes it as far as the driver’s seat, keys in the ignition, feet braced on the pedals below. He could. He could start it up, peel off and peel out, leave Sam here until the worst of it's over and send Cas to mop up the mess. It's pretty obvious that he's not making much difference to Sam. Kid doesn't even recognise him. Hell, if anything he’s probably making it worse, his face in Sam’s nightmares while he’s right there beside him blurring the lines between hallucination and what’s real.

Cas might be Sam’s friend, now, but Dean could really do with having him here; even if all he’d be able to do is to look concerned and to say to Dean, “That isn’t your brother in there.”

Of course, that’s exactly the problem. It is Sam. All of it. The good bits and the bad bits and the really fucking annoying bits, the stuff Dean wants to exorcise to get back to some mythical core which will turn out to be the _real_ Sam, who he’s been missing for so long. It’s a joke, right? It’s impossible. It’s a lie. This is Sam. This is Sam. And Dean has to find a way to stop searching for some imaginary little brother who’s maybe never been there, and to try to find out how to be big enough and good enough for the man who _is_.

And that means… that means not walking out. Dean’s done it before, often enough: turned tail and left Sam desperate or near-suicidal behind him. He left Sam alone in the panic room at Bobby’s, because he couldn’t handle watching the kid suffer. He left Sam spiralling and isolated after what happened with Gadreel, left because he was wrestling his own guilt and couldn’t stand to have Sam add more. But it’s more than that. He might not always run away, not physically, not every time, but he’s master of the emotional withdrawal. Even he knows that. Sam’ll come to him with those big worried eyes and he’ll try to say something comforting, offer up his tender belly and Dean will say something sardonic, shift into mocking and prickly where Sam’s been vulnerably sincere.

Dean closes his eyes. The image of Sam, chugging down demon blood for Dean’s sake, presents itself.

“Fuck,” he says. “Fuck, okay,” and gets out of the car.

~~~

 

The hallucinations finally let up about two days later, leaving Sam mute and miserable, sweating and shivery in turn. This, though, Dean feels better able to manage; finds himself finally confident bringing Sam water and sugar and soup.

“You’re doing awesome, kiddo,” he says.

“I’m not a baby,” Sam mumbles, but he lets Dean baby him; lets Dean run him a bath and even, shamefaced, asks Dean to wash his hair. “All my joints hurt when I try to lift my arms,” he says.

Dean doesn’t quibble (doesn’t mention, either, the more intimate care he’s had to take of his brother these last few days), just pulls up a chair beside the bathtub and does as he’s told, watches the grime and the sweat and the vomit of the days since they left the bunker bleed out of Sam’s hair and into the water and down the drain.

Sam’s so beaten up. He’s skinny, even skinnier, that’s what three days without eating will do. He’s bruised all over; and where he isn’t bruised, he’s cut, the scratches down his arms still dark and stark against his pale while skin. But he’s here, and it could be worse.

This isn’t a fix. Dean knows that down the road ahead of them is the bunker, with the blood that he spilt soaked into the floorboards and the bedrooms where they both lie awake. It isn’t a fix. But he did stick through this, saw Sam through this, and that has to count for something.

When Sam gets out of the bath he puts on his jeans, notches his belt a couple holes tighter around his waist, and then pulls Dean’s grey hoodie over his head. It’s big on him, which is disorientating.

“Okay,” Sam says, and he walks stiffly out of the door to the car. Dean’s loaded it already, and he stays just a second to look over the room, make sure they left nothing behind them.

Leaning against the doorframe, looking back into the bedroom, Dean runs a steadying hand down over his face. The soiled sheets, all of them, are piled in the centre of the room; and despite his best efforts with the open window, the whole place reeks of vomit and blood. He’s gonna be glad to leave. There were a good few moments over the past few days when he thought that Sam might die here; might die thinking that he was alone, too out of his mind to know that Dean was there.

“Hey,” says Sam, behind him.

Dean turns. His brother is standing beside the car, the sunlight making a halo of his hair.

“You okay?” Sam says.

“Yeah,” says Dean. “Yeah.”

He closes the motel door behind him, walks towards where Sam is standing. Their eyes meet, and Dean steps closer, giving into the urge to run his fingers through the sun-golden curls behind Sam’s ear. Sam catches his hand, brings it up to his mouth. He touches his lips to the inside of Dean's wrist, the pulse-point.

"Thanks for staying with me," Sam says.

Dean smiles, reclaims his hand. He knocks his fist against Sam's still-wobbly shoulder: gently, gently, so his brother doesn't break. "Hey, bro. Don't need to thank me. Just returning the favour,” he says.

Sam nods, almost imperceptibly, and then turns away, heads around the car to climb into his seat. Dean watches him. ‘Not never’, Sam had said. And looking at him, Dean starts to believe it. It isn’t never. It’s just ‘not yet’.

**Author's Note:**

> Thanks so much for reading, guys, and especially for leaving comments. This one's a beast and a labour of love so I'd love to hear your thoughts.


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